Strategies to increase the ownership and use of insecticide‐treated bednets to prevent malaria
Abstract
Background
Malaria is a life‐threatening parasitic disease and 40% of the world's population lives in areas affected by malaria. Insecticide‐treated bednets (ITNs) effectively prevent malaria, however, barriers to their use have been identified.
Objectives
To assess the evidence on the effectiveness of available strategies that focus on delivery and appropriate use of ITNs.
Search methods
We searched the EPOC Register of Studies, CENTRAL, MEDLINE, EMBASE, HealthStar, CINAHL, PubMed, Science Citation Index, ProQuest Dissertations and Theses, African Index Medicus (AIM), World Health Organization Library and Information Networks for Knowledge
(WHOLIS), LILACS, Virtual Health Library (VHL), and the World Health Organization Library Information System (WHOLIS). Initial searches were conducted in May 2011, updated in March 2012 and February 2013. Authors contacted organizations and individuals involved in ITN distribution programs or research to identify current initiatives, studies or unpublished data, and searched reference lists of relevant reviews and studies.
Selection criteria
Randomized controlled trials, non‐randomized controlled trials, controlled before‐after studies, and interrupted time series evaluating interventions focused on increasing ITN ownership and use were considered. The populations of interest were individuals in malaria‐endemic areas.
Data collection and analysis
Two authors independently screened studies to be included. They extracted data from the selected studies and assessed the risk of bias. When consensus was not reached, any disagreements were discussed with a third author. The magnitude of effect and quality of evidence for each outcome was assessed.
Main results
Of the 3032 records identified, 10 studies were included in this review.
Effect of ITN cost on ownership:
Four studies including 4566 households and another study comprising 424 participants evaluated the effect of ITN price on ownership. These studies suggest that providing free ITNs probably increases ITN ownership when compared to subsidized ITNs or ITNs offered at full market price.
Effect of ITN Cost on appropriate use of ITNs:
Three studies including 9968 households and another study comprising 259 individuals found that there is probably little or no difference in the use of ITNs when they are provided free, compared to providing subsidized ITNs or ITNs offered at full market price.
Education:
Five studies, including 12,637 households, assessed educational interventions regarding ITN use and concluded that education may increase the number of adults and children using ITNs (sleeping under ITNs) compared to no education.
One study, including 519 households, assessed the effects of providing an incentive (an undisclosed prize) to promote ITN ownership and use, and found that incentives probably lead to little or no difference in ownership or use of ITNs, compared to not receiving an incentive.
None of the included studies reported on adverse effects.
Authors' conclusions
Five studies examined the effect of price on ITN ownership and found moderate‐certainty evidence that ownership was highest among the groups who received the ITN free versus those who purchased the ITN at any cost. In economic terms, this means that demand for ITNs is elastic with regard to price. However, once the ITN is supplied, the price paid for the ITN probably has little to no effect on its use; the four studies addressing this outcome failed to confirm the hypothesis that people who purchase nets will use them more than those who receive them at no cost. Educational interventions for promoting ITN use have an additional positive effect. However, the impact of different types or intensities of education is unknown.
PICOs
Plain language summary
Strategies to increase the ownership and use of insecticide‐treated bednets to prevent malaria
Researchers in the Cochrane Collaboration conducted a review of the effect of different strategies to increase people’s ownership and use of insecticide‐treated bednets to prevent malaria. In February 2013 they identified 10 relevant studies. Their findings are summarized below.
What is malaria and how can insecticide‐treated bednets prevent it?
Malaria is a life‐threatening disease caused by a parasite. A person becomes infected from being bitten by a mosquito carrying the parasite. People with malaria may have symptoms such as chills, fever, vomiting, diarrhea, and jaundice. About 40% of the world’s population is at risk of malaria, mostly in the poorest countries.
Insecticide‐treated bednets fit over a bed and act as a barrier between insects and the person sleeping. The bednets are dipped in insecticide, a chemical that kills or repels mosquitoes and effectively prevent malaria. Insecticide‐treated bednets cost money and it is important to find ways of ensuring that people who need them own them. Even when people own bednets they may not always use them properly. To be effective, bednets need to be used every night. They must also hang properly and be treated with enough insecticide. It is important to measure whether different strategies not only increase people's ownership but also people's use of bednets.
What this research says:
The studies included in this review took place in Africa and India. In five of the studies, people were either given insecticide‐treated bednets free, or could buy them at a subsidized price or full market price. In the other five studies, people were educated about how to use the bednets properly, for instance through visits at home or through information on the radio, on television and in the community. The included studies show the following:
Providing free insecticide‐treated bednets:
‐ Probably increases the number of people who own bednets compared to providing subsidized bednets or bednets offered at full market price.
‐ Probably leads to little or no difference in the use of bednets compared to providing subsidized bednets or bednets offered at full market price.
Providing education for the appropriate use of insecticide‐ treated bednets:
‐ May increase the number of adults and children under five using bednets (sleeping under bednets).
Providing incentives to encourage use of insecticide‐treated bednets:
‐ Probably leads to little or no difference in ownership or use of bednets compared to those who did not receive an incentive.
A possible side effect when providing free or subsidized insecticide‐treated bednets may be that the governments and institutions who pay for the bednets take this money from other priority issues. However, none of the included studies measured whether these or any other side effects had occurred.
Authors' conclusions
Summary of findings
| Cost, education, and social marketing interventions to increase ITN ownership and use for malaria prevention | ||||
| Patient or population: Adults (including pregnant women) and children | ||||
| Outcomes | Impact | No of Participants | Quality of the evidence | Comments |
| Distributing ITNs free compared to making ITNs available for purchase through different mechanisms | ||||
| ITN ownership among pregnant women, adults and children | Free ITN distribution probably increases the number of pregnant women, adults and children who own ITNs compared to providing subsidized ITNs or ITNs offered at full market price.1 | 5090 (5 studies)2 | ⊕⊕⊕⊝ moderate certainty3 | Dupas 2009 noted that an increase in price from no cost to 1 USD led to a 35% drop in take‐up; and a 25% drop as price increased from 1 USD to 2 USD.4 |
| Appropriate use | Free ITN distribution probably leads to little or no difference in rates of usage of ITNs compared to providing subsidized ITNs or ITNs offered at full market price. | 8837 (4 studies)5 | ⊕⊕⊕⊝moderate certainty6 | |
| Education about appropriate ITN use compared with no ITN use education | ||||
| ITN use by adults (any ITN use) | May increase the number of adults using ITNs (including sleeping under ITNs). | 889 | ⊕⊕⊕⊝ | |
| ITN use by children under 5 | May increase the number of children under 5 years old using ITNs (including sleeping under ITNs). | 11,748 | ⊕⊕⊝⊝ | |
| Providing incentives to encourage ITN use compared to no incentives | ||||
| Use (net mounted) | Providing incentives to encourage ITN use probably leads to little or no difference in ITN use compared to those who did not receive an incentive. | 519 (1 study)11 | ⊕⊕⊕⊝ | |
| Adverse events | Not reported. | |||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||
| GRADE Working Group grades of evidence | ||||
| Adverse events were not reported in the studies. | ||||
| 1One study provided free ITNs to pregnant women, subsidized ITNs and social marketing to the community and compared this to control communities with access to subsidized ITNs and social marketing (Muller 2008). The second study provided women attending prenatal clinics with free ITNs , KES 10, KES 20, or KES 40 (Cohen 2010). 2 The studies included in this outcome are Cohen 2010, Dupas 2009, Fink 2012, Muller 2008, and Tarozzi 2011. Cohen 2010 included 424 participants and the remainder of the studies reported the number of households (4666 households). 3Baseline imbalances for most variables in the Muller 2008 study and some outcomes mentioned in the protocol were not reported in the final study. The Cohen 2010 study has small sample sizes in each of the 4 groups. Unclear ROB. Baseline characteristics of study participants not described and some mismanagement (leakage) of ITNs. The Dupas 2009 study had small samples sizes in each price group and unclear ROB. The Tarozzi 2011 study had unclear method of randomization and the intervention and control clients may have different characteristics. Allocation concealment was not described in Fink 2012. Some baseline differences between groups (fewer sleeping spaces in the control group, fewer ITNs at baseline in the free group). 4Dupas 2009 randomly assigned households to a subsidy level for ITNs (40% to 100%). ITN cost ranged from free to KES 300 (USD 4.62). Households received a voucher to obtain their net at the randomly assigned price. They were also assigned a "marketing" group (health vs. financial framing vs. none), a "commitment" group, and a "targeting" group (female head of household, male head, or both) (Dupas 2009). 5The included studies are Cohen 2010, Dupas 2009, Fink 2012, and Tarozzi 2011. Cohen included 259 participants and the remaining studies included 9968 households. 6Downgraded because of inconsistency. 7 Included studies are Amoran 2012 and Krezanoski 2010. The latter compared education with incentives vs no education or incentives. The number of participants reflects the number of households since these studies measured use at the household level. 8Baseline imbalances in the Amoran 2012 study (knowledge about appropriate ITN mounting was higher in the intervention group at baseline). 9Included studies are De La Cruz 2009, Deribew 2012, and Keating 2012. The number of participants reflects the number of households since these studies measured use at the household level. 10Baseline imbalances in all three studies in which ITN use was higher in the intervention groups. Inconsistency between studies (De La Cruz 2009; Deribew 2012; Keating 2012). Deribew 2012 is a CBA. 11The included study is Krezanoski 2010. 12Single study with small sample size (Krezanoski 2010). | ||||
Background
Malaria is a life‐threatening parasitic disease transmitted by female Anopheles mosquitoes. Malaria has the highest impact on young children who have not yet developed acquired immunity. In pregnant women, malaria is associated with increased risk of severe anemia, low birth weight, as well as with an increase in miscarriages and maternal deaths (Desai 2007; WHO 2010b). According to the World Health Organization (WHO) World Malaria Report 2014, there were 198 million cases of malaria and 584,000 deaths in 2013, of which 78% were among children under five years old (WHO 2014). Approximately 40% of the world's population is at risk of malaria; those at risk are primarily in the world's poorest countries.
Malaria causes a significant economic burden at both the individual and the regional level; it has an enormous and long‐lasting effect on economic growth and development. Malaria contributes to localized differences in gross domestic product (GDP) between countries with and without malaria, especially in Africa. The WHO states that in some countries personal and public spending on costs related to malaria accounts for up to “40% of public health expenditures, 30% to 50% of inpatient hospital admissions, [and] up to 60% of outpatient health clinic visits.” The costs of malaria are borne disproportionately by those who can afford them the least: the poor and those who have limited access to health services (WHO 2010b).
The increase in international funding for fighting malaria has resulted in better access to malaria‐preventive measures (WHO 2010c), including insecticide‐treated bednets (ITNs) (Lengeler 2004); and indoor residual spraying and screens (Morel 2005; Pluess 2010). ITNs can reduce malaria mortality by 55% for children under 5 in sub‐Saharan Africa(WHO 2014). However, the proportion of children under five years and pregnant women sleeping under ITNs is much lower than the coverage rates (Alaii 2003; Eisele 2009a). According to surveys conducted in Africa between 1999 and 2004, the median proportion of children under five sleeping under ITNs was only 3%. In countries with subsidized or free‐of‐charge ITN distribution, use has been scaled up successfully (WHO 2014). By 2013, ITN ownership increased in Africa: 49% of households owned at least one ITN and 44% of children slept under one (WHO 2014). Increased funding contributed to the rapid rise in the number of ITNs procured and distributed within countries. For example, between 2004 and 2006 the Global Fund increased ITN funding from USD 1.35 million to USD 18 million and between 2004 and 2007 the United Nations Children's Fund (UNICEF) increased its procurement from 7 million ITNs to nearly 20 million (UNICEF 2007). The number of ITNs delivered by manufacturers in sub‐Saharan Africa increased from 11 million in 2005 to 392 million in 2013. This suggests that ITN use was scaled up effectively in countries with subsidized or free ITNs (WHO 2014). Globally, 83 countries with ongoing malaria transmission provide free ITNs to all age groups (WHO 2014).
One of the barriers to the effective ownership and use of ITNs is the associated cost. For example, one Kenyan study found that although rural residents wanted to own and use ITNs, they could not afford them (Guyatt 2002). It was estimated that ITNs for an entire household would cost about the same as paying for three children to attend one year of primary school (Guyatt 2002). Another barrier to ITN use is that people are often unfamiliar with ITNs, or do not have a habit of using them, so they need to be convinced of their usefulness and persuaded to use them on a regular basis (WHO 2010a). The culture of ITN use is more developed among some ethnic groups and this has a significant impact on ITN coverage. Wealth, living in an urban rather than rural area and higher levels of education are other important factors positively associated with ITN ownership and use, and their impacts on coverage need to be assessed (Belay 2008; Eisele 2009b; Monasch 2004).
Description of the intervention
WHO defines an insecticide‐treated bednet (ITN) as a "mosquito net that repels, disables and/or kills mosquitoes coming into contact with insecticide on the netting material" (WHO 2007). Appropriate use of ITNs requires that they are hanging correctly and that they are used consistently (Eisele 2009b).
Strategies to increase ownership and use of ITNs include social marketing, health education campaigns by multidisciplinary teams, developing a 'net culture' through promotion and publicity, increased availability (e.g. local production of high‐quality ITNs), free ITN distribution campaigns and cost reduction (e.g. reduced taxes imposed on ITNs) (WHO 2010a).
In the preceding decade, there has been much controversy over how ITNs should be distributed. This controversy can be roughly summarized as social marketing of subsidized ITNs versus free distribution of ITNs (Curtis 2003; Lines 2003). Social marketing of ITNs applies methods of commercial marketing, such as advertising, and includes the provision of ITNs through voucher schemes or direct sales in which the purchaser pays a portion of the product’s cost, with public sources financing the difference (Armstrong Schellenberg 1999). Free distribution entails the provision of free ITNs at selected points of care, such as antenatal clinics, and mass campaigns of regional or national provision, usually in tandem with other health interventions (Lengeler 2007). Many, probably most, of these ITNs were freely distributed and many were piggybacked on other public health campaigns, such as immunization campaigns (Grabowsky 2005; Grabowsky 2007).
Why it is important to do this review
While mass distribution of ITNs is necessary, it is not sufficient to ensure mass use of ITNs. Therefore, it is important to identify strategies that will both increase the ownership of ITNs and encourage appropriate use. This review assesses current evidence on strategies to increase ownership and use of ITNs and addresses a global health issue that is a core part of the United Nations’ Millennium Development Goal (MDG) number six, which aims to 'Combat HIV/AIDS, Malaria and other diseases' (UN 2008). This review can help policy‐makers and practitioners make appropriate and evidence‐based decisions regarding ITN programs to help roll back malaria by identifying effective strategies to increase the ownership and appropriate use of ITNs, and the contexts and populations in which these strategies are effective.
Objectives
To assess the evidence on the effectiveness of available strategies that focus on delivery and appropriate use of ITNs.
Methods
Criteria for considering studies for this review
Types of studies
In this review, we included studies that reported on strategies that may increase ownership and the appropriate use of ITNs. Evaluating these interventions using randomized controlled trials (RCTs) may be challenging since scale‐up strategies are delivered at a population level and are the standard of care in at‐risk populations (WHO 2010c). Further, achieving unbiased randomization is difficult for a vector‐borne disease where geographic displacement of short distances between comparators (under a kilometre) may result in differences affecting the vector’s ecology and disease transmission. Thus, we also considered non‐randomized trials in our review.
We considered any study design meeting the study design criteria from the Cochrane Effective Practice and Organisation of Care Group (EPOC 2014a). Studies considered were: RCTs; cluster RCTs; non‐randomized controlled trials; controlled before‐after studies (CBAs) with contemporaneous data collection and with two or more control and intervention sites; and interrupted time series studies (ITSs) with a clearly defined point in time when the intervention occurred and at least three data points before and after implementation of the intervention.
Types of participants
We included children and adults with permanent residence in malarious areas. Participants could include individuals or groups of individuals (e.g. families, households). We excluded military populations, travelers, students, those living in transient refugee camps for less than one malaria season, and others not permanently residing in the study area. These groups were excluded because their characteristics differ from the characteristics of populations that permanently reside in these areas since they may have greater access to ITNs and other malaria‐preventive measures. For example, in addition to ITNs, military populations may have access to mosquito repellents and antimalarial drugs that are not available to ordinary residents (Ockenhouse 2005).
Types of interventions
Our systematic review included both unifaceted and multifaceted interventions that aimed to increase the ownership and appropriate use of ITNs. Unifaceted interventions are interventions with only one component (e.g. ITN distribution only), whereas multifaceted interventions consist of two or more components (e.g. free ITNs bundled with education about appropriate ITN use). To clarify the relationship between the interventions and the outcomes (Tugwell 2010), we developed a logic model (Figure 1). Interventions are grouped into three main categories depending on their focus: increasing ITN ownership (through delivery strategies), appropriate use of ITNs, and combinations of these.
LOGIC MODEL: Strategies to increase the use of insecticide‐treated nets in households and vulnerable populations to reduce morbidity and mortality from malaria in endemic settings
ITN Ownership
The framework by Kilian 2010 was adapted and incorporated into our logic model (Figure 1 and Figure 2). Kilian's framework is a descriptive categorization of the various components of ITN delivery strategies intended to increase ITN ownership. Categories that are defined by this framework include ITN delivery channel, duration of distribution, cost to user, choice of ITN in terms of net preference and accessibility, and sectors involved in the distribution (Kilian 2010).
Framework of components of interventions to increase the ownership and use of ITNs
Appropriate ITN Use
Interventions focusing on appropriate ITN‐use strategies were categorized using a logic model that builds on Kilian's framework (Figure 1 and Figure 2) (Kilian 2012). Examples of interventions to increase use are campaigns to increase ITN hang‐up and volunteer home visits to educate populations about the appropriate use of ITNs. Interventions to encourage appropriate use can be delivered through different channels (community, outreach, routine services and at retail points). These interventions can be provided during limited periods of time (single or repeated) or they can be ongoing (continuous). Appropriate‐use interventions can be delivered by the public sector (e.g. government) or private sector (civil society; non‐governmental organizations (NGOs); faith‐ and community‐based organizations; and the commercial sector). Interventions are further categorized as those focusing on education, peer monitoring (e.g. volunteer home visits), or publicity (e.g. media). We reported relevant context information that may affect the appropriate use of ITNs (e.g. national/regional culture, ITN stock‐out periods, nomadic lifestyle).
Comparison groups included no intervention and other strategies aiming to increase ITN use (e.g. comparing two different interventions that are aiming to increase ITN use). We excluded studies focusing solely on the effectiveness of ITNs. Excluded studies informed the background and discussion sections of the review.
Types of outcome measures
Primary outcomes
ITN Ownership
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Proportion of households with at least one ITN.
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Proportion of households with people/ITN ratio ≤ 2.0 among households with any bednets.
Appropriate ITN Use
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Proportion of existing ITNs used.
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Proportion of population sleeping under ITNs.
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Proportion of pregnant women sleeping under ITNs.
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Proportion of children under five years sleeping under ITNs.
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Proportion of households with all children under five years sleeping under ITNs.
We included measures of ITN use during the previous night and measures of ITN use for which the timeframe of use was not reported.
Secondary outcomes
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Equity ratio of household ownership with ITNs calculated across household income.
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Child all‐cause mortality.
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Child malaria‐specific mortality.
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Child malaria morbidity.
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All‐cause mortality.
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Malaria‐specific mortality.
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Malaria‐specific morbidity.
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Anemia in pregnant women.
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Low birth weight.
We included these secondary outcomes since ownership and appropriate use of ITNs will result in measurable differences in these clinical outcomes, as demonstrated in a previous systematic review (Lengeler 2004). Our outcome measures are congruent with the Roll Back Malaria Monitoring & Evaluation Reference Group (MERG) minimum standards recommended for assessing malaria impact in countries in sub‐Saharan Africa (Kilian 2011; Roll Back Malaria Partnership 2008).
We planned to record any adverse or any unintended effects reported (e.g. unable to afford other necessities due to money used by households to purchase ITNs).
Search methods for identification of studies
The initial search was conducted in May 2011. Updates of the initial search were conducted in March 2012 and February 2013. Search results are reported in a PRISMA flow diagram (Figure 3) (Moher 2009).
Study flow diagram.
The EPOC Trials Search Coordinator developed search strategies (Appendix 1) in consultation with the authors. They comprise keywords and controlled vocabulary terms for malaria or parasites causing malaria in humans (Plasmodium falciparum/malariae/ovale/vivax and insecticide‐treated bednets or mosquito nets). Language limits were not applied. Databases were typically searched from database start date forward; dates of database coverage are provided in the list of databases below. Two methodological search filters were used to limit retrieval to appropriate study design and interventions of interest: the Cochrane RCT Sensitivity/Precision Maximizing Filter (cf. the Cochrane Handbook for Systematic Reviews of Interventions 6.4d); and an EPOC Filter to identify study designs including CBA, ITS, and other quasi‐experimental designs acceptable in EPOC reviews.
Databases
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The Cochrane Central Register of Controlled Trials (CENTRAL), part of The Cochrane Library.www.thecochranelibrary.com [2013, Issue 1]
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MEDLINE, OVID [1948 to February 2013]
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EMBASE, OVID [1947 to February 2013]
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HealthStar, OVID [1999 to February 2013]
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Cumulative Index to Nursing and Allied Health Literature CINAHL, EbscoHost [1980 to February 2013]
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The EPOC Specialised Register, Reference Manager [2013, Issue 1]
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PubMed [up to February 2013]
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Science Citation Index, Social Sciences Citation Index [1975 to February 2013 (Web of Science)
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Dissertations and Theses, ProQuest [1861 to February 2013]
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African Index Medicus (AIM), World Health Organization (WHO) [up to February 2013]
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Latin American and Caribbean Health Sciences database (LILACS), Virtual Health Library (VHL) [up to February 2013]
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World Health Organization Library Information System (WHOLIS) [WHO publications, 1948 to February 2013; WHO journals & technical documents, 1986 to February 2013]
Searching other resources
Other systematic reviews
Related systematic reviews were identified by searching the Database of Abstracts of Reviews of Effectiveness (DARE) and the databases listed above.
Gray literature
An extensive gray literature search was conducted. Gray literature sites were identified using a list of databases relevant to low‐ and middle‐income countries and websites compiled by the EPOC Group's Norwegian satellite office (http://epocoslo.cochrane.org/lmic‐databases) and Grey matters: a practical search tool for evidence‐based medicine (http://cadth.ca/resources/grey‐matters). Search strategies for these databases and web sites were simpler than those used in mainstream databases such as MEDLINE and EMBASE. Gray literature sites, search terms, and number of results are provided in Appendix 2.
Additionally, we:
a) Reviewed reference lists of relevant systematic reviews and studies selected for inclusion in this review.
b) Contacted authors of relevant studies or reviews to clarify reported published information or to seek unpublished results/data.
c) Contacted agencies that either conduct studies or provide funding for malaria interventions and requested data from unpublished and ongoing studies. These agencies included UNICEF, United Nations Foundation, International Federation of Red Cross and Red Crescent Societies, World Health Organization, United States Agency for International Development (USAID), the Johns Hopkins Bloomberg School of Public Health, Population Services International (PSI), World Bank, World Vision, and Alliance for Malaria Prevention.
d) Conducted reference searches on studies selected for inclusion in this review, studies cited in related reviews, and other relevant citations in ISI Web of Science/Web of Knowledge.
Data collection and analysis
The data collection and analysis were conducted following the guidelines available in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).
Selection of studies
Two individuals independently screened all titles and abstracts for potentially relevant studies. Full‐text copies of all papers that were deemed potentially eligible by consensus of two authors were retrieved and screened against the inclusion criteria. Any disagreement about the eligibility was resolved by discussion between the two review authors and by consulting a third review author as necessary.
Data extraction and management
Two review authors independently undertook data extraction from the full text of each eligible study based on the EPOC Data Collection Checklist (EPOC 2010). Any disagreement was resolved by discussion between the two review authors and consultation with a third author if required. If any data were missing, we contacted the relevant corresponding authors. We collected data for specific populations (e.g. pregnant women, low socioeconomic status) for use in subgroup analyses, as described below.
Assessment of risk of bias in included studies
Two review authors independently assessed risk of bias for included studies. For RCTs, we assessed the risk of bias using the Cochrane Collaboration’s 'Risk of bias' tool (Higgins 2011), which assesses the following domains: generation of randomization sequence, allocation concealment, blinding of participants and providers, blinding of outcome assessors, selective outcome reporting, incomplete outcome data, and other sources of bias (e.g. major baseline differences, etc.). We assessed each potential source of bias and graded as high, low or unclear. A justification for our judgment is reported in the 'Risk of bias' tables. Any disagreement about the risk of bias was resolved by discussion between two authors, and with a third review author when necessary. Due to the characteristics of interventions that we explored in our review, blinding of study participants and providers was not possible. However, lack of blinding was still considered a high risk of bias.
For other study designs, we used the risk of bias criteria suggested by EPOC:
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generation of allocation sequence;
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concealment of allocation;
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baseline outcome measurements;
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baseline characteristics;
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incomplete outcome data;
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blinding of outcome assessor;
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protection against contamination;
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independence of intervention from other changes (ITS only);
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pre‐specified shape of the intervention (ITS only);
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intervention unlikely to affect data collection (ITS only);
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selective outcome reporting; and
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other risks of bias (EPOC 2014b).
Measures of treatment effect
We reported pre‐intervention and post‐intervention means or proportions for both study and control groups. For any baseline imbalances, we calculated unadjusted and adjusted absolute change from baseline with 95% confidence intervals (CIs), where baseline results were available from RCTs, non‐randomized controlled trials, and CBAs. We accounted for existing ITNs when reported by authors.
Additionally, we reported findings separately for RCTs, non‐randomized controlled trials, and CBAs.
Unit of analysis issues
Where possible, we attempted to re‐analyse data with potential unit of analysis errors. In cluster‐randomized trials, a cluster is the unit of allocation. The cluster refers to a group of individuals enrolled in the study such as medical clinic patients, villages or families. The individuals within a cluster may be more similar in their characteristics than they are to individuals in other clusters. Therefore, it would be incorrect to analyse the data as if the individual participants were the unit of allocation. For cluster‐randomized trials with unit‐of‐analysis errors, we used statistical methods to perform the analysis at the individual level while accounting for inter‐cluster correlation. We used the Cochrane Handbook for Systematic Reviews of Interventions' methods to calculate the variance inflation factor (Higgins 2011). Eight of the ten included studies were cluster RCTs (cRCT). Muller 2008 required re‐analysis because the sampling unit within the clusters was households and data in the paper were presented for individuals. Muller 2008 reported using a design effect of two to account for potential intra‐cluster correlation (ICC). To calculate CIs, we adjusted the observed proportions using the design effect of two as reported in the study (Muller 2008). The other cRCTs were deemed to be appropriately analysed as they considered the unit of randomization to be at the cluster level (Amoran 2012; Cohen 2010; Dupas 2009; Fink 2012; Keating 2012; Krezanoski 2010; Tarozzi 2011).
Dealing with missing data
We attempted to obtain missing data from the authors of the included studies. When this was not possible, we performed the analysis using only the available data. We explored the impact of missing data on the review findings in the Discussion section of our review.
Assessment of heterogeneity
We described the variability of interventions identified in our review using a logic model and framework (Figure 1 and Figure 2). We planned to explore heterogeneity using forest plots and the I² statistic, if possible. We planned to perform Chi² tests and evaluate P values using 0.10 as a cut‐off point. The importance of I² would depend on the strength of evidence of heterogeneity (P value from Chi² test or a CI for I²) and on the magnitude and direction of effects.
Assessment of reporting biases
We planned to use funnel plots to explore the possibility of publication bias, if 10 or more studies were included in any meta‐analysis and if studies were of different sizes. We would have visually inspected funnel plots for asymmetry and explored reasons for asymmetry. However, we did not include 10 or more studies in the meta‐analysis.
Data synthesis
We performed data synthesis using Review Manager 5.1 (RevMan) (RevMan 5.1). We reported the overall number of studies included in the review and the main research questions addressed. We synthesized information about study methods (e.g. study design, duration of intervention, follow‐up); participants (e.g. sex/gender, age, country, setting); intervention (e.g. intervention description and its components, means of delivery, methods of communication); setting (for both control and intervention group if available); outcomes (list of outcomes and time points reported); and notes (other details of the study that do not fall under mentioned categories). We commented on study designs, analytical methods, risk of bias, generalizability and relevance of study results as well as other important study characteristics.
We reported the outcomes of interest as published in the original papers. Due to lack of standardization of outcomes, we were only able to pool the results from two studies for the outcome "nets owned per capita (measured as nets owned)" (Fink 2012; Tarozzi 2011). We used a random‐effects model for this analysis and a generic inverse‐variance model of analysis. When other outcomes were similar, we reported the direction of the effect (e.g. we considered "households with at least one ITN" and "households with appropriately hanging ITNs" as similar outcomes). Some outcome measurements are considered more reliable than others (e.g. inspection of ITNs in the house versus self‐reporting of the use of the ITN), so we also reported the outcomes grouped by the way in which the outcome was assessed, if appropriate.
We included the magnitude of the effects of the interventions and the quality of evidence, by summarizing available data on each of the outcomes of interest. We included both relative and absolute measures of effect when possible.
We reported effect sizes for each included study using risk ratios (RRs) and odds ratios (ORs) (random‐effects models) with 95% CIs. Where possible, we have used RRs. For four studies, we have reported ORs for some outcomes, as reported by the study authors. These results were analyzed using logistic regression as the baseline data required to convert these to RRs were not available. Where studies reported more than one measure for each endpoint, we abstracted the primary measure (as defined by the authors of the study).
We compared included studies with an emphasis on explanation for potential differences between study results, taking into account the context where the intervention was implemented. We included a table that summarizes characteristics and findings of included studies in a consistent and systematic manner (Table 1), following our logic model and framework (Figure 1 and Figure 2).
|
| ITN delivery mechanisms | Appropriate ITN use interventions | |||||||
| Study overview | Channel | Duration | Cost to User | Choice of type and time | Sector | Channel | Duration | Type of intervention | Sector |
| AMORAN 20121 | ‐‐ | ‐‐ | ‐‐ | ‐‐ | ‐‐ | Community | Single | Education (provided to nursing mothers) | Civil society |
| COHEN 20102 | Routine Service | Single | Free, Subsidized (90% to 100%) | No choice of ITN type; | Public | ‐‐ | ‐‐ | ‐‐ | ‐‐ |
| DE LA CRUZ 20093 | ‐‐ | ‐‐ | ‐‐ | ‐‐ | ‐‐ | Community (during bank meetings) | Single | Education | Civil society (NGO Freedom from Hunger (FFH)) |
| DERIBEW 20124 | Unclear (ITNs provided by UNICEF but delivery channel unclear) | Single | Free | No choice of ITN type; | Unclear whether delivered by members of the study team or the trained village residents | Civil society (Community members received training of trainers then gave training to heads of households in the intervention villages) | Single | Education (tailored training of household heads) | Civil society |
| DUPAS 20095 | Community (voucher given during house‐to‐house visit); | Single | Free, Subsidized (40% to 100%) | No choice of ITN type; | Commercial | Community (house‐to‐house visit) | Single | Education | Civil society (study personnel) |
| FINK 20126 | Other (research project staff) | Single (study campaign) | Free, partially subsidized (50%) for loan group, and market price for controls | No choice of ITN type; Time unclear | Civil society (research project) and private (cotton company) | ‐‐ | ‐‐ | ‐‐ | ‐‐ |
| KEATING 20127 | Other (Universal ITN delivery in rural areas provided by National Malaria Control Center and PATH Malaria Control and Evaluation Partnership in Africa) | ‐‐ | ‐‐ | ‐‐ | ‐‐ | Community | Single (study campaign) | Education (community health workers) | Civil Society and public (PATH Malaria Control and Evaluation Partnership in Africa and the Zambian Ministry of Health) |
| KREZANOSKI 20108 | Community (voucher given during house‐to‐house visit); | Single | Free (coupons) | No choice of ITN type; | Civil society (NGO distribution site) | Other (ITNs study team site in the town) | Single | Education | Civil society (NGO Population Services International ‐ PSI) |
| MULLER 20089 | Community | Unclear (possibly free ITNs in prenatal clinics and subsidized ITNs available in stores after the study campaign) | Free (prenatal clinics); subsidized (local retailers) | No choice of ITN type; Time ‐ unclear (subsidized and free ITNs possibly available and after the study) | Public (prenatal clinics); Commercial (local retailers) | Community | Single | Education (Information, Education and Communication (IEC activities)); publicity (radio and television messages, poster exhibition, community‐based information) | Civil society (NGO Population Services International ‐ PSI) |
| TAROZZI 201110 | Community | Single | Free, Market price | Limited choice of ITN type (choice of size; | Civil society | Community | Single | Education | Civil society (NGOBharat Integrated Social Welfare Agency ‐ BISWA) |
1.Intervention: a one day educational program based on the national malaria control program provided to nursing mothers. Comparison: households selected from a different town receiving no intervention.
2. 20 prenatal clinics were assigned to different subsidy levels:
(5 clinics ‐ ITNs free of charge; 5 clinics ‐ KES 10 (97.5% subsidized); 5 clinics ‐ KES 20 (95.0% subsidy); 3 clinics ‐ KES 40 (90% subsidy); 5 clinics = control + lottery on announced random day for additional discount
3.Intervention: Malaria education
Comparison: 1. Attention placebo of diarrhea education; 2. No education
4.Intervention: Training of heads of households (education with posters, manuals and demonstrations on appropriate long‐lasting (LL) ITN use); Free LLITN; Monthly monitoring of appropriate use and malaria occurrence with appropriate LLITN use training; Three times a year mass blood examination for anemia and malaria of children under five and pregnant women
Comparison: Free LLITN; Monthly monitoring of malaria occurrence; Three times a year mass blood examination for anemia and malaria of children under five and pregnant women
5.Intervention: Households were assigned to
1. A subsidy level (40% to 100%);
2. One of three “marketing” groups ("health framing", "financial framing" and no marketing message);
3. One of two “commitment” groups (verbal commitment; no verbal commitment to buy LLITN);
4. One of three “targeting” groups (voucher given to female head of the household, male head or both heads)
Single‐headed households were excluded.
Comparison: Intervention groups were compared
6.Intervention: In the free group, households could receive one ITN for each sleeping space. In the loan group, households could get ITNs at 50% subsidized cost with repayment due at the end of the harvesting season. The maximum number of ITNs each household could receive was restricted to the number of sleeping spaces in the household.
Comparison: ITNs for sale at market price.
7.Intervention: Community‐based interpersonal communication intervention delivered through community health workers (CHWs). CHWs provided information about malaria transmission, prevention, and ITNs.
Comparison: CHWs provided an HIV awareness campaign to their communities.
8. Intervention: Voucher for an ITN and undisclosed "prize" promised for appropriate use;
Comparison: Voucher for an ITN; no incentive promised
Note: ITNs came with instructions in the local language explaining how to mount the bednet over a bed
9.Intervention 1: Access to subsidized ITNs + free ITNs available to pregnant women through prenatal clinics + social marketing;Interveniton 2: Access to subsidized ITNs + social marketing
10.Intervention: 1. Microlender BISWA offered contracts for the purchase of ITNs and re‐treatments (ITN price was not subsidized);
+ brief information campaign on malaria and bednets
2. Free ITNs + brief information campaign on malaria and bednets
Comparison: No ITN distribution program or education on malaria and bednets
We assessed the certainty of evidence for each primary outcome using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach and the GRADEpro software (Guyatt 2008a). The certainty of the evidence may be downgraded for factors such as study limitations, inconsistency of results, imprecision, indirectness of evidence, or publication bias. Factors that increase the certainty of the evidence include a large magnitude of effect, plausible confounding, and dose‐response gradient (Guyatt 2008b). Finally, we presented the main findings in 'Summary of findings' tables.
Subgroup analysis and investigation of heterogeneity
We planned to conduct subgroup analyses to explore heterogeneity, according to the following study characteristics: the type of intervention as per the logic model (Figure 1 and Figure 2) (e.g. cost to end user); specific population characteristics (e.g. gender/sex, ethnicity, geographic areas, rural/urban, socioeconomic status, education, age/subgroup (children under five years and pregnant women)); and the number and type of interventions in each strategy. However, we had insufficient data to complete these planned subgroup analyses.
We also extracted details on the above subgroup analyses conducted within the included studies.
Results
Description of studies
See: Characteristics of included studies; Characteristics of excluded studies.
Results of the search
Our search strategy yielded 3032 references. During the abstract screening process, we excluded 2899 references for failing to meet one or more inclusion criteria. The remaining 133 references were reviewed as full‐text, plus an additional three studies identified through reference‐list checking and two identified through personal communication with experts. We excluded 117 studies that did not meet our eligibility criteria and excluded eight others after obtaining information from the study authors. Thirteen studies met our eligibility criteria and ten were included in our review. Of the remaining three studies, two are ongoing and one requires additional information from the authors. For details please see Figure 3 and the Characteristics of excluded studies table. Full results from the gray literature searches are available on request.
Included studies
Ten studies were included in this review: eight cluster RCTs (Amoran 2012; Cohen 2010; Dupas 2009; Fink 2012; Keating 2012; Krezanoski 2010; Muller 2008, Tarozzi 2011); one RCT (De La Cruz 2009); and one CBA study (Deribew 2012). Nine of the included studies included 17,203 households (Amoran 2012; De La Cruz 2009; Deribew 2012; Dupas 2009; Fink 2012; Keating 2012; Krezanoski 2010; Muller 2008; Tarozzi 2011). The remaining study reported by individual and included 424 participants (Cohen 2010).
Additionally, three other studies were eligible but not included: one study is awaiting classification (Soleimani Ahmadi 2012); and the two remaining studies are ongoing (Kilian 2012; Siekmans 2012).
Study participants
Study participants in our review were recruited in rural Africa (Amoran 2012; Cohen 2010; De La Cruz 2009; Deribew 2012, Dupas 2009; Fink 2012; Keating 2012; Krezanoski 2010; Muller 2008); and rural India (Tarozzi 2011). They belong to several categories: adults who were enrolled during household visits (Krezanoski 2010; Dupas 2009); pregnant women enrolled through prenatal clinics (Cohen 2010; Muller 2008); mothers of children under five years old (Amoran 2012); adults and women of reproductive age enrolled using client lists of NGOs that offer financial services in the community (De La Cruz 2009; Tarozzi 2011); rural cotton farmers (Fink 2012); heads of households, pregnant women, and children under five (Deribew 2012), and all households in selected villages (Keating 2012).
Characteristics of intervention
Interventions in studies included in our review aimed to increase the ownership or use of ITNs. We categorized them according to the logic model developed for this review in which interventions are divided into those focusing on different ITN delivery strategies (to increase ITN ownership) and those interventions focusing on appropriate use (Figure 1 and framework in Figure 2). A detailed classification of interventions used in each included study can be found in Table 1 in which the included studies are mapped according to the logic model.
Five included studies used a combination of strategies focusing on ITN delivery to increase ITN ownership and appropriate use (Cohen 2010, Dupas 2009, Krezanoski 2010, Muller 2008, Tarozzi 2011). One study focused on delivery strategies to increase ownership only (Fink 2012) and four studies examined appropriate use strategies (Amoran 2012, De La Cruz 2009, Deribew 2012, Keating 2012).
Delivery strategies to increase ITN ownership included administering the intervention through routine services (e.g. prenatal clinics) (Cohen 2010; Muller 2008); or administering the intervention in the community (e.g. house‐to‐house visits) (Dupas 2009; Fink 2012; Krezanoski 2010; Tarozzi 2011).
Interventions to promote the appropriate use of ITNs were provided mainly through the community (Amoran 2012; Dupas 2009; De La Cruz 2009; Deribew 2012; Keating 2012; Muller 2008; Tarozzi 2011). Different educational methods were used to increase the use of ITNs. These included: training for household heads (Deribew 2012); house‐to‐house visits to teach the population how to appropriately hang and use an ITN, educational sessions plus printed materials (Amoran 2012; Keating 2012); and train‐the‐trainer education sessions (De La Cruz 2009). Appropriate ITN‐use interventions were available as one‐time activities (e.g. during house‐to‐house visits (Dupas 2009); or during the whole duration of the campaign (e.g. Muller 2008 used long‐term ITN social marketing); and were coordinated by civil society or the public sector, mainly by NGOs with local community services involved (Deribew 2012; Dupas 2009; Muller 2008; Keating 2012). Some studies identified pregnant women and children under the age of five as populations of special interest (Amoran 2012; Cohen 2010; De La Cruz 2009; Deribew 2012; Keating 2012; Tarozzi 2011).
The interventions in all studies were part of campaign evaluation and were of a relatively brief duration. Furthermore, study participants could choose the type of ITN in only one study ‐ in this study participants could choose the size of the ITN they purchased (Tarozzi 2011). When evaluating the cost to end users, ITNs were provided to study participants free (Amoran 2012; Cohen 2010; Deribew 2012; Dupas 2009; Fink 2012; Keating 2012; Krezanoski 2010; Muller 2008); partially subsidized (Cohen 2010; Dupas 2009; Muller 2008; Fink 2012); and at a full market price (Fink 2012; Tarozzi 2011). The public sector (e.g. prenatal clinics) (Cohen 2010; Fink 2012; Keating 2012; Muller 2008), the commercial sector (e.g. local retailers) (Dupas 2009; Muller 2008), and civil society (e.g. NGOs) (Deribew 2012; Dupas 2009; Krezanoski 2010; Tarozzi 2011) were involved in the distribution of ITNs.
Outcomes measured
The outcomes reported in the identified studies were ITN ownership, ITN use, and malaria morbidity. Outcomes measured in pregnant women or children under the age of five were reported separately as these populations are identified as vulnerable groups.
Excluded studies
Eighteen articles were identified as potentially eligible during the full text screening, of which eight articles referring to seven studies were excluded from the review (Characteristics of excluded studies). Studies were excluded for the following reasons: not an eligible study design, or they assessed the efficacy of ITNs rather than a strategy to increase ownership, use, or both.
Risk of bias in included studies
The risk of bias for each included study is described in the Characteristics of included studies and shown in Figure 4 and Figure 5.
Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Allocation
Selection bias was assessed as low in most studies (Cohen 2010; Dupas 2009; Fink 2012; Krezanoski 2010; Tarozzi 2011). The method of randomization was unclear for four studies (Amoran 2012; De La Cruz 2009; Keating 2012; Muller 2008). One study was a non‐randomized study and assessed as high risk for selection bias (Deribew 2012).
Blinding
Assessment of outcomes was both objective (e.g. visual observation of ITN being used, blood tests for malaria parasite and hemoglobin levels) (Cohen 2010; Deribew 2012; Fink 2012; Krezanoski 2010; Muller 2008); and subjective (e.g. self‐reported ITN use) (Amoran 2012; Cohen 2010; Dupas 2009; De La Cruz 2009; Fink 2012; Keating 2012; Krezanoski 2010; Muller 2008; Tarozzi 2011). Cohen 2010 used blinding for both study participants and the individuals involved in the intervention administration by not disclosing that ITN use would be evaluated. However, due to the nature of the interventions (e.g. distributing free ITNs), blinding of study participants or assessors was not always possible. In Deribew 2012, the same individuals who administered the intervention also collected outcome data.
Incomplete outcome data
The risk of bias for incomplete outcome data reporting was assessed as unclear in nine of the studies, because data on attrition and loss to follow‐up were not fully reported (Amoran 2012; Cohen 2010; Dupas 2009; De La Cruz 2009; Fink 2012; Keating 2012; Krezanoski 2010; Muller 2008; Tarozzi 2011). The Deribew 2012 study had a high number of dropouts which was not explained by the authors and therefore was assessed as being at high risk of bias.
Selective reporting
Muller 2008 was the only study that provided a study protocol. This study did not report all the outcomes described in the protocol (e.g. costs per malaria case, insecticide content on ITN, acceptance of health staff and population) and thus the risk of bias for selective reporting was assessed as high. Deribew 2012 described the study methods and baseline results in a separate publication and all outcomes assessed at baseline were assessed post‐intervention. Therefore, this study was assessed as low risk of bias. The risk of bias for selective reporting was assessed as unclear for the remaining studies (Amoran 2012; Cohen 2010; De La Cruz 2009; Dupas 2009; Fink 2012; Keating 2012; Krezanoski 2010; Tarozzi 2011).
Other potential sources of bias
One study was reported to be at high risk of other sources of bias as it did not include any objective measures of ITN use following the educational intervention and relied on self‐reported ITN use (Amoran 2012).
Five of the studies were evaluated to have unclear risk for other potential sources of bias for reasons described below (Cohen 2010; De La Cruz 2009; Dupas 2009; Keating 2012; Muller 2008).
Cohen 2010 observed some leakages and mismanagement of ITNs in 4 of 11 clinics asked to sell ITNs at a positive price. In De La Cruz 2009 there was a difference in the characteristics of study participants at baseline between the intervention and the control groups.
Keating 2012 found that some lay or community health workers (CHW) delivered the intervention to control group communities and the results indicate that some control houses received information about malaria or assistance with hanging a net. Additionally, the intervention group had higher ITN use at baseline. The authors also reported contamination across communities, with 47% of children in the intervention communities living in houses reporting exposure to the CHW intervention and 31% of children in control houses reporting the same exposure (Keating 2012).
Two studies observed some differences in participants' characteristics at baseline (Deribew 2012, Muller 2008). Dupas 2009 did not report on similarity in baseline characteristics between the intervention and the control groups enrolled in their study so the risk of other potential sources of bias was unclear.
Other potential sources of bias were not observed or suspected in the other three included studies (Fink 2012; Krezanoski 2010; Tarozzi 2011).
Effects of interventions
See: summary of findings Table for the main comparison
The results are reported by intervention, as described in the logic model.
Impacts of distributing free ITNs compared to making ITNs available for purchase through different mechanisms
The five studies that broadly addressed this comparison indicate overall that providing free ITNs probably increases the number of people who own ITNs compared to providing subsidized ITNs or ITNs offered at the full market price (moderate‐certainty evidence) (Dupas 2009; Cohen 2010; Muller 2008; Fink 2012; Tarozzi 2011). The studies also indicate that providing free ITNs probably leads to little or no difference in usage of ITNs, compared to providing subsidized ITNs or ITNs offered at the full market price (moderate‐certainty evidence).
The following section reports the results of the specific comparisons separately. Where an outcome is not listed, it was not assessed by the studies in that comparison.
Comparison 1: Free ITN compared to paying for an ITN (range of costs)
Three studies addressed this comparison (Dupas 2009; Cohen 2010; Muller 2008). Overall, these studies found that providing free ITNs probably increases ITN ownership compared to providing subsidized ITNs or ITNs at market price (moderate‐certainty evidence) (summary of findings Table for the main comparison).
The first study was conducted in rural Kenyan villages and evaluated four different interventions and their impact on ITN ownership and use among children and adults (Dupas 2009). In this study, households were randomly assigned to: a subsidy level (from 40% to 100% subsidy); one of three “marketing” groups (health framing, financial framing or no marketing); one of two “commitment” groups (verbal commitment or no verbal commitment); and one of three “targeting” groups (male head, female head, or both female and male head of household) (Dupas 2009). The effect of the "marketing", "commitment", and "targeting" interventions on use are presented later.
The second study included pregnant women from rural Kenya and compared the impact of different levels of subsidy for ITNs on ITN ownership and use (Cohen 2010). ITNs in this study were provided either free; or for KES 10 (approximately $0.15 USD; 97.5% subsidy); or KES 20 (approximately $0.30 USD; 95% subsidy); or KES 40 (approximately $0.60 USD; 90% subsidy).
Muller 2008 was conducted in rural Burkina Faso and evaluated the effect of social marketing with and without free distribution of ITNs to pregnant women through prenatal clinics. Highly subsidized ITNs were available for the whole study area.
Ownership
Three studies assessed this outcome (Cohen 2010; Dupas 2009; Muller 2008).
The Dupas 2009 study found that receiving a free ITN probably increases ITN ownership. ITN ownership was the highest among the free group compared to those who paid any price (RR 3.02, 95% CI 2.78 to 3.30, moderate certainty evidence) (Analysis 6.1). Dupas 2009 observed that an increase in price from no cost to USD 1 reduces ITN ownership among households by 35% and an increase in price from USD 1 to USD 2 reduces ITN take‐up by an additional 25% (Dupas 2009) (Analysis 1.1; Analysis 2.1; Analysis 3.1; Analysis 4.1; Analysis 5.1).
Cohen 2010 found that providing free ITNs probably increases ITN ownership compared to those providing ITNs at any price point (RR 1.29. 95% CI 1.25 to 1.33, moderate‐certainty evidence) (Analysis 10.1).
Free distribution of ITNs to pregnant women plus social marketing probably increases ITN ownership compared to social marketing alone (RR 1.49, 95% CI 1.14 to 1.95, moderate‐certainty evidence) (Analysis 11.1) (Muller 2008).
Appropriate use
Overall, the two studies that assessed this outcome found that free ITN distribution probably leads to little or no difference in appropriate ITN use, compared to providing subsidized ITNs or ITNs offered at the full market price (moderate‐certainty evidence).
Dupas 2009 reported that there is probably little to no difference in ITN usage between those who received the ITN at no cost and those who paid for it (moderate‐certainty evidence) (Analysis 1.2; Analysis 2.2; Analysis 3.2; Analysis 4.2; Analysis 5.2).
Cohen 2010 also found that there is probably no pattern of increasing use with increasing ITN price. Specifically, the study noted that there was probably little to no difference in ITN usage between those who received the ITN free and those who paid KES 10, 20, or 40 (moderate‐certainty evidence) (Analysis 7.2; Analysis 7.3; Analysis 8.2; Analysis 8.3; Analysis 9.2; Analysis 9.3).
Secondary outcomes
Equity ratio of household ownership
The included studies did not contain enough information to calculate the equity ratio of household ownership of ITNs according to household income. Dupas 2009 reported observational data that baseline wealth and financial access predicted ITN ownership but, once purchased, they did not predict ITN use. In the same study, baseline educational levels of household members (male or female) did not predict ITN ownership (Dupas 2009). Cohen 2010 reported that women who paid KES 40 for their ITN were slightly more likely to pay for transportation to the clinic, to be literate and to be wearing shoes when attending the clinic.
Comparison 2: Free ITN compared to ITN available for purchase using a microfinance loan
Two studies assessed this comparison (Fink 2012; Tarozzi 2011).
Fink 2012 had three arms: a control group who did not receive the intervention; a group that received free ITNs (up to one ITN for each uncovered sleeping space); and a loan group who could obtain one ITN per sleeping space at 50% subsidized cost. The loan group was required to repay the loan by the end of the harvest period.
Tarozzi 2011 conducted a large‐scale study in rural India. The study had three arms: a control group that did not receive the intervention (ITNs were available at market price); a group that received free ITNs based on household composition (free group); and a group that was offered microfinance loans (due to be repaid in one year) (MF group). These loans could be used to purchase ITNs or re‐treatments. Outcomes related to ITN ownership, ITN use, anemia and malaria infection status were reported. ITN use was measured both with self report and with direct observation (Tarozzi 2011).
Ownership
The pooled data for Fink 2012 and Tarozzi 2011 suggest that receiving an ITN at no cost probably increases ITN ownership, compared to purchasing an ITN at the market price (SMD 0.69, 95% CI 0.39 to 0.99, moderate‐certainty evidence) (Analysis 12.1) or purchasing an ITN using a loan (SMD 0.37, 95% CI 0.27 to 0.47, moderate‐certainty evidence) (Analysis 14.1). There is probably little to no difference in ITN ownership when comparing groups in which ITNs were purchased using a loan and those in which ITNs were purchased at the market price (SMD 0.29, 95% CI ‐0.06 to 0.63, moderate‐certainty evidence) (Analysis 13.1).
Appropriate use
Fink 2012 found that there was probably little to no difference in ITN use between those who received a free ITN and those who bought ITNs using a loan or at the market price. Approximately 90% of households in all three arms were using ITNs when assessed at follow‐up. The mean difference in ITN use (measured as ITNs seen hanging at follow‐up) was:
-
1.42 higher in the free group compared to control;
-
0.79 higher for the microfinance group compared to control; and
-
0.63 higher for the free group compared to the microfinance group (moderate‐certainty evidence).
Tarozzi 2011 noted that self‐reported ITN use was probably lower in the microfinance group than in the free group for the previous night (OR 0.74, 95% CI 0.68 to 0.79, moderate‐certainty evidence) (Analysis 14.4) and during the peak season (OR 0.66, 95% CI 0.61 to 0.72, moderate‐certainty evidence) (Analysis 14.3). Field staff were able to verify the usage of ITNs in 93% of free households and 89% of microfinance households.
Secondary outcomes
Malaria‐specific morbidity in children
Fink 2012 found that children under 15 years in the groups receiving free ITNs or through loans were probably less likely to report confirmed malaria than controls (Free group versus control: OR 0.547, 95% CI 0.231 to 0.993; Loan group versus control: OR 0.444, 95% CI 0.213 to 0.924, moderate‐certainty evidence) (Fink 2012). Among children under 5 years old in the Tarozzi 2011 study, malaria prevalence was 11% in the control group but 18.4% in the free group and 19.8% in the microfinance group.
Malaria‐specific morbidity in adults
Fink 2012 noted that the number of confirmed cases of malaria in adults over 15 years was probably fewer in the free and loan groups compared to controls (Free group versus control: OR 0.361, 95% CI 0.122 to 1.072, moderate certainty evidence; Loan group versus control: OR 0.307, 95% CI 0.106 to 0.887, moderate‐certainty evidence) (Fink 2012).
Impacts of interventions to promote the appropriate use of ITNs
Five studies assessed the impacts of educational interventions on the appropriate use of ITNs (De La Cruz 2009, Deribew 2012, Keating 2012, Amoran 2012, Krezanoski 2010). These studies found that providing an educational intervention may increase the number of adults and children using ITNs (sleeping under ITNs), compared to controls (summary of findings Table for the main comparison).
Comparison 1: Malaria education versus an attention placebo of diarrhea education
De La Cruz 2009, conducted through a microfinance association that uses a 'Credit with Education' program in rural Ghana, compared three groups. One group of clients of the microfinance association received education about malaria; another group of clients received education about diarrhea prevention; and a third group from the same communities who were not clients of the microfinance association did not receive any educational intervention. Participants in the third group were not randomly selected and therefore have not been included in this review.
The malaria education curriculum consisted of 10 interactive sessions between 40 minutes and one hour in duration. The sessions included topics such as malaria transmission, where ITNs are sold, developing a plan to increase ITN use, identifying signs of serious malaria, the importance of chemoprophylaxis during pregnancy, and actions to improve prevention and treatment of malaria in the community (De La Cruz 2009). Participants who received diarrhea education learned about preventing and treating diarrhea through seven sessions. The follow‐up time was approximately two years.
Ownership
Participation in malaria education sessions may increase ownership of ITNs (RR 2.01, 95% CI 1.08 to 3.74, low‐certainty evidence), compared to participating in diarrhea education sessions (Analysis 15.1) (De La Cruz 2009).
Appropriate use
Providing education about malaria to parents may increase use of ITNs, measured by the number of children sleeping under an ITN (RR 2.36, 95% CI 1.02 to 5.46, low‐certainty evidence), compared to providing diarrhea education (De La Cruz 2009) (Analysis 15.2).
Secondary outcomes
This study did not report on any of the secondary outcomes for the review.
Comparison 2: Malaria education for heads of households versus no education
The Deribew 2012 study was conducted in a malaria‐endemic area in Ethiopia. The intervention included free ITNs and training for the heads of households on the appropriate use of ITNs. The comparison group received free ITNs but no training. Nine intervention village residents received a five‐day training course for trainers on the appropriate use of ITNs. These village residents then offered training to all household heads in the intervention villages. ITN use was measured by direct observation by trained village residents (Deribew 2012).
Ownership
Ownership was not measured in this study.
Appropriate use
The study suggests that malaria education may increase ITN use among children under five years of age at both six‐months follow‐up (RR 1.20, 95% CI 1.16 to 1.24, low‐certainty evidence) (Analysis 16.1); and twelve‐months follow‐up (RR 1.60, 95% CI 1.52 to 1.68, low‐certainty evidence) (Deribew 2012) (Analysis 16.2), compared to diarrhea education.
Secondary outcomes
Malaria‐specific morbidity in children
Children under 5 years old in the intervention group were less likely to be anemic than those in the control group at both 6‐months and 12‐months follow‐up (Deribew 2012).
Malaria‐specific morbidity in adults
In Deribew 2012, fewer participants in the intervention group reported having had a fever within the last two weeks at six‐months follow‐up (RR 0.29, 95% CI 0.26 to 0.31, low‐certainty evidence) (Analysis 16.3); and twelve‐months follow‐up (RR 0.19, 95% CI 0.16 to 0.22, low‐certainty evidence), compared to those in the control group (Analysis 16.4).
This study did not report on any of the other secondary outcomes.
Comparison 3: Malaria education provided by community health workers versus no education
In the cluster randomized trial conducted by Keating 2012, lay or community health workers (CHWs) delivered an interpersonal communication intervention to mothers and heads of households that focused on providing information about malaria transmission and prevention through the use of ITNs. CHWs gave information about ITN repair and re‐treatment, who should use ITNs, and their importance year round. The CHWs also provided information to motivate individuals to use ITNs, such as information on the effectiveness of ITNs for malaria prevention. This information was provided through house‐to‐house visits using visual aids and information pamphlets. Community plays and demonstrations were also held. CHWs were trained to provide on‐site assistance with hanging ITNs including provision of any required materials (e.g. string, nails, or hammers) and repairing ITNs.
Ownership
This study did not report on ITN ownership.
Appropriate use
The study found that malaria education by CHWs may increase ITN use among children under five years (OR 2.24, 95% CI 1.46 to 3.44, low‐certainty evidence) (Analysis 17.2) and any ITN use in the house (OR 2.06, 95% CI 1.35 to 3.14, low‐certainty evidence) (Analysis 17.1), compared to no education.
Secondary outcomes
This study did not report on any of the secondary outcomes.
Comparison 4: Malaria education provided to nursing mothers versus no education
Amoran 2012 provided a structured educational program based on the national malaria control program's course content (Amoran 2012). Nursing mothers from rural communities of Ogun State, Nigeria, were randomized to receive the intervention. The intervention consisted of a one‐day training session of three units: malaria transmission, malaria prevention and treatment, and malaria practices. Participants were surveyed three months after the intervention to assess utilization of ITN and knowledge about malaria.
Ownership
This study did not report on ITN ownership.
Appropriate use
This study found that malaria education probably increases ITN use (self‐reported), compared to no education (RR 2.29, 95% CI: 1.82 to 2.89, moderate‐certainty evidence) (Analysis 18.1) (Amoran 2012).
Secondary outcomes
This study did not report on any secondary outcomes.
Comparison 5: Education with incentives versus no incentives on appropriate use of ITNs
In the cluster randomized trial by Krezanoski 2010, all study participants received a free ITN. However, the intervention communities were promised an undisclosed prize at one‐month follow‐up if they complied with the appropriate use of ITNs. A final follow‐up home visit to assess ITN use was conducted by surveyors at six months to check for mounted ITNs.
Ownership
Participants in both groups were provided with free ITNs and there was no difference in ITN ownership between intervention and control groups (Analysis 19.1).
Appropriate use
This study found that providing incentives plus education probably leads to little to no difference in ITN use (measured by visual inspection for mounted nets) at one‐month follow‐up (RR 1. 10, 95% CI 0.94 to 1.28, moderate‐certainty evidence) and six‐months follow‐up (RR 1.00, 95% CI 0.95 to 1.07, moderate‐certainty evidence), compared to not providing incentives (Analysis 19.2) (Krezanoski 2010).
Secondary outcomes
This study did not report on any of the secondary outcomes.
Impacts of a combination of ITN delivery mechanisms and interventions to promote the appropriate use of ITNs
One study assessed the effects of implementation factors (Dupas 2009). The interventions evaluated are described above.
Ownership
The study found there is probably little to no difference in ITN ownership between a group that received a health‐framing marketing message versus no framing and a group that received a financial‐framing marketing message versus no framing (moderate‐certainty evidence) (Analysis 20.1; Analysis 21.1). Additionally, there is probably little to no difference in ITN ownership when vouchers are given to either female heads versus both heads jointly or male heads versus both heads jointly or when there is a verbal commitment to purchase an ITN versus no verbal commitment (Analysis 22.1, Analysis 23.1, Analysis 24.1, moderate‐certainty evidence) (Dupas 2009).
Appropriate use
The study found there is probably little to no difference in appropriate ITN use between a group that received a health‐framing marketing message versus no framing and a group that received a financial‐framing marketing message versus no framing (Analysis 20.2; Analysis 21.2, moderate‐certainty evidence). Additionally, there is probably little to no difference in appropriate ITN use when vouchers are given to either female household heads versus both heads jointly or male heads versus both heads jointly or when there is a verbal commitment to purchase an ITN versus no verbal commitment (Analysis 22.2, Analysis 23.2, Analysis 24.2, moderate‐certainty evidence) (Dupas 2009).
Secondary outcomes
Secondary outcomes were not assessed for this comparison.
Adverse Effects
None of the included studies reported on adverse effects of the intervention.
Discussion
Summary of main results
The five included studies that examined the impact of ITN price on ownership found that ownership was highest when ITNs were available free, which indicates that ITNs may be acquired by those in lower socioeconomic groups when the cost is decreased (Cohen 2010; Dupas 2009; Fink 2012; Muller 2008; Tarozzi 2011). These studies varied the cost of ITNs: two provided ITNs at varying subsidized prices, one compared free ITNs distributed to pregnant women in prenatal clinics to subsidized ITNs for the general population, and two studies compared loans to free distribution (Cohen 2010; Dupas 2009; Fink 2012; Muller 2008; Tarozzi 2011).
Secondly, education about the appropriate use of ITNs may increase appropriate use, compared to no education intervention or an attention placebo (diarrhea education). This effect was found regardless of whether ITNs were available free or for a cost within the community (De La Cruz 2009), and when education was tailored for the household heads (Deribew 2012), or given to mothers (Amoran 2012). Thirdly, ITN use was not affected by other factors such as whether an incentive (such as prizes) was offered (Krezanoski 2010).
Four studies failed to confirm the hypothesis that people who purchase nets will use them more than those who receive them free (Cohen 2010; Dupas 2009; Fink 2012; Tarozzi 2011). These studies show that there is probably little or no difference in rates of ITN use among those who receive a free ITN compared to those who pay for one.
Overall completeness and applicability of evidence
The studies included in this review are very heterogeneous. The studies were conducted in diverse populations in low‐ and middle‐income countries, with nine of the ten studies undertaken in rural Africa (Amoran 2012; Cohen 2010; De La Cruz 2009; Deribew 2012, Dupas 2009; Fink 2012; Keating 2012; Krezanoski 2010; Muller 2008) and one in rural India (Tarozzi 2011). Geographic location may impact the effectiveness of ownership and use strategies, depending on the burden of malaria in that setting.
A recent survey, conducted in Ethiopia, indicates that it may not be enough to educate people about appropriate use of ITNs unless other potential barriers are identified and addressed. Respondents reported not using an ITN the previous night for the following reasons: the ITN was considered to be too old, too badly damaged, too dirty, or unavailable for use because it was being cleaned (Batisso 2012). Our review did not identify barriers preventing ITN use as we focused on interventions to promote use. However, the findings of Batisso 2012 are important for identifying the reasons ITNs are not used.
There were not enough data available in the included studies to assess the impact of different strategies on the equity ratio of household ownership and appropriate use of ITNs. Two studies reported on observational analyses of household wealth and ITN ownership and use: Dupas 2009 found that baseline wealth and financial access predict ITN ownership but, once purchased, they do not predict ITNs' use. Keating 2012 found little to no difference in ITN use by children according to household wealth. However, this information was not presented separately for intervention and control groups.
None of the included studies reported on whether the authors looked for or found any evidence relating to adverse effects. However, interventions that provide subsidized or free ITNs to the community may create resource allocation issues by diverting resources from other priority issues to ITN delivery strategies.
Quality of the evidence
Most of the included studies were well‐designed cluster randomized studies that provided very detailed descriptions of the methods used and were assessed to be at low risk of bias (Figure 3). The risk of bias was high for blinding of participants for all studies (Figure 4) since all study participants were aware of their assignment to delivery strategies such as free ITNs or education about ITNs. One study was assessed as high risk of bias because of contamination between study groups (Keating 2012).
Potential biases in the review process
Publication bias was not explored formally in this review as we had too few studies to develop a meaningful funnel plot. Studies with negative findings may be reported in the gray literature rather than peer‐reviewed journals. We tried to minimize this risk by using a comprehensive search strategy including searching numerous gray literature sources and websites, and contacting experts.
Six of the included studies had missing data and required additional information from the authors (Cohen 2010; De La Cruz 2009; Dupas 2009; Fink 2012; Muller 2008; Tarozzi 2011). This information related to adjusting for clustering, relative risk calculations, random sequence generation, and allocation concealment. The authors of six of these studies provided the additional data needed to complete this review.
We attempted to reduce additional sources of bias through the development of a logic model. This model helped us to clearly define our search terms and develop our inclusion/exclusion criteria, especially with regard to outcomes (Anderson 2011). We also involved a number of stakeholders in the development of the logic model which led to a more robust model (Kellogg 2004).
Agreements and disagreements with other studies or reviews
Previous systematic reviews by Willey and colleagues reviewed the scale‐up of different malaria prevention strategies, including ITNs, intermittent preventive treatment in pregnancy, and artemisinin combination treatment (Willey 2010; Willey 2012). These reviews included both qualitative and quantitative study designs. The Willey 2012 review included nine studies that reported an equity ratio for ITN ownership according to socioeconomic status and found that ownership was highest among households in the poorest quintile in four studies and higher in the least poor quintile in five studies. Both reviews by Willey and colleagues found that strategies which delivered free ITNs achieved high ownership and use, and this is in agreement with the results of this review. Although we were unable to determine the equity ratio of ITN ownership, an equity effect is consistent with our results that ITN ownership is higher when ITNs are available free or at a reduced cost.
Sexton 2011 examined best practices for ITN distribution to ensure satisfactory ITN coverage and malaria control. They found that best practices included a combination of delivering free ITNs and a "catch up" component. For example, a "catch‐up" program may include free or subsidized ITN distribution during routine immunization days within areas with low coverage (Sexton 2011). This approach is in agreement with our findings that ITN ownership increases as cost decreases.
A recent survey, conducted in Nigeria, assessed the effect of a free mass distribution campaign on the equity of ITN ownership (Ye 2012). This study did not have a control group and was therefore excluded from our review. However, the study found similar results. This study concluded that free mass distribution campaigns appear to be more effective than other strategies intended to increase ITN ownership, such as social marketing campaigns and subsidized ITNs (Ye 2012).
LOGIC MODEL: Strategies to increase the use of insecticide‐treated nets in households and vulnerable populations to reduce morbidity and mortality from malaria in endemic settings
Framework of components of interventions to increase the ownership and use of ITNs
Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Risk of bias summary: review authors' judgements about each risk of bias item for each included study.
Comparison 1 ITN Price: free vs. KES 210 to 300, Outcome 1 Ownership (purchased net).
Comparison 1 ITN Price: free vs. KES 210 to 300, Outcome 2 Use (ITN seen hanging after 2 months, if purchased).
Comparison 1 ITN Price: free vs. KES 210 to 300, Outcome 3 ITN used by children.
Comparison 1 ITN Price: free vs. KES 210 to 300, Outcome 4 ITN used by adults.
Comparison 2 ITN Price: free vs. KES 160 to 200, Outcome 1 Ownership (purchased net).
Comparison 2 ITN Price: free vs. KES 160 to 200, Outcome 2 Use (ITN seen hanging after 2 months, if purchased).
Comparison 2 ITN Price: free vs. KES 160 to 200, Outcome 3 ITN used by children.
Comparison 2 ITN Price: free vs. KES 160 to 200, Outcome 4 ITN used by adults.
Comparison 3 ITN Price: free vs. KES 100 to 150, Outcome 1 Ownership (purchased net).
Comparison 3 ITN Price: free vs. KES 100 to 150, Outcome 2 Use (ITN seen hanging after 2 months, if purchased).
Comparison 3 ITN Price: free vs. KES 100 to 150, Outcome 3 ITN used by children.
Comparison 3 ITN Price: free vs. KES 100 to 150, Outcome 4 ITN used by adults.
Comparison 4 ITN Price: free vs. KES 70 to 90, Outcome 1 Ownership (purchased net).
Comparison 4 ITN Price: free vs. KES 70 to 90, Outcome 2 Use (ITN seen hanging after 2 months, if purchased).
Comparison 4 ITN Price: free vs. KES 70 to 90, Outcome 3 ITN used by children.
Comparison 4 ITN Price: free vs. KES 70 to 90, Outcome 4 ITN used by adults.
Comparison 5 ITN Price: free vs. KES 40 to 60, Outcome 1 Ownership (purchased net).
Comparison 5 ITN Price: free vs. KES 40 to 60, Outcome 2 Use (ITN seen hanging after 2 months, if purchased).
Comparison 5 ITN Price: free vs. KES 40 to 60, Outcome 3 ITN used by children.
Comparison 5 ITN Price: free vs. KES 40 to 60, Outcome 4 ITN used by adults.
Comparison 6 ITN Price: free vs. any price (KES 40 to 300), Outcome 1 ITN ownership (purchased net).
Comparison 7 ITN price: free vs. KES 40, Outcome 1 Ownership (measured as a share of prenatal clients who acquired program ITN).
Comparison 7 ITN price: free vs. KES 40, Outcome 2 ITNs use (self reported at follow‐up).
Comparison 7 ITN price: free vs. KES 40, Outcome 3 ITN use (net seen hanging at follow‐up).
Comparison 8 ITN price: free vs. KES 20, Outcome 1 Ownership (measured as a share of prenatal clients who acquired program ITN).
Comparison 8 ITN price: free vs. KES 20, Outcome 2 ITNs use (self reported at follow‐up).
Comparison 8 ITN price: free vs. KES 20, Outcome 3 ITN use (net seen hanging at follow‐up).
Comparison 9 ITN price: free vs. KES 10, Outcome 1 Ownership (measured as a share of prenatal clients who acquired program ITN).
Comparison 9 ITN price: free vs. KES 10, Outcome 2 ITNs use (self‐reported at follow‐up).
Comparison 9 ITN price: free vs. KES 10, Outcome 3 ITN use (net seen hanging at follow‐up).
Comparison 10 ITN price: free vs any cost (KES 10 to 40), Outcome 1 ITN ownership.
Comparison 11 Free ITNs, access to subsidized ITNs and social marketing vs. access to subsidized ITNs and social marketing, Outcome 1 No of households with at least one intervention ITN.
Comparison 11 Free ITNs, access to subsidized ITNs and social marketing vs. access to subsidized ITNs and social marketing, Outcome 2 Number of households with at least one ITN.
Comparison 11 Free ITNs, access to subsidized ITNs and social marketing vs. access to subsidized ITNs and social marketing, Outcome 3 Last night of bednet (%).
Comparison 12 Free ITN vs. Control, Outcome 1 Nets owned per household (measured as nets owned).
Comparison 12 Free ITN vs. Control, Outcome 2 Use (nets used per household, seen at follow‐up).
Comparison 12 Free ITN vs. Control, Outcome 3 Usual ITN use in peak season.
Comparison 12 Free ITN vs. Control, Outcome 4 Slept under a net the night before the survey.
Comparison 12 Free ITN vs. Control, Outcome 5 Malaria positive (total).
Comparison 12 Free ITN vs. Control, Outcome 6 Anaemia (Hb< 11g/dL).
Comparison 13 Microfinancing for nets vs. Control, Outcome 1 Nets owned per household (measured as nets owned).
Comparison 13 Microfinancing for nets vs. Control, Outcome 2 Use (nets used per household, seen at follow‐up).
Comparison 13 Microfinancing for nets vs. Control, Outcome 3 Usual ITN use in peak season.
Comparison 13 Microfinancing for nets vs. Control, Outcome 4 Slept under a net the night before the survey.
Comparison 13 Microfinancing for nets vs. Control, Outcome 5 Malaria positive (total).
Comparison 13 Microfinancing for nets vs. Control, Outcome 6 Anaemia (Hb< 11g/dL).
Comparison 14 Free ITN vs. Microfinancing for nets, Outcome 1 Nets owned per capita (measured as nets owned).
Comparison 14 Free ITN vs. Microfinancing for nets, Outcome 2 Use (nets used per household, seen at follow‐up).
Comparison 14 Free ITN vs. Microfinancing for nets, Outcome 3 Usual ITN use in peak season.
Comparison 14 Free ITN vs. Microfinancing for nets, Outcome 4 Slept under a net the night before the survey.
Comparison 14 Free ITN vs. Microfinancing for nets, Outcome 5 Malaria positive (total).
Comparison 14 Free ITN vs. Microfinancing for nets, Outcome 6 Malaria positive (children under 15).
Comparison 14 Free ITN vs. Microfinancing for nets, Outcome 7 Anaemia (Hb< 11g/dL).
Comparison 15 Malaria education vs. Diarrhea education, Outcome 1 Owns at least one ITN.
Comparison 15 Malaria education vs. Diarrhea education, Outcome 2 Children under 5 sleeping under ITN.
Comparison 16 Educating Heads of Households in proper ITN use, Outcome 1 ITN utilization by under‐five children at 6 months follow up.
Comparison 16 Educating Heads of Households in proper ITN use, Outcome 2 ITN utilization by under‐five children at 12 months.
Comparison 16 Educating Heads of Households in proper ITN use, Outcome 3 Had fever in last 2 weeks (self reported at 6 months).
Comparison 16 Educating Heads of Households in proper ITN use, Outcome 4 Had fever in last 2 weeks (self reported at 12 months).
Comparison 17 CHW‐provided intervention vs. control, Outcome 1 Any ITN use in house (at follow up).
Comparison 17 CHW‐provided intervention vs. control, Outcome 2 ITN use among children <5 (at follow‐up).
Comparison 18 Education provided to nursing mothers vs. control, Outcome 1 Prevalence of ITN use (ever use ITN).
Comparison 19 Free ITN + undisclosed incentive for use vs. free ITN alone, Outcome 1 ITN ownership.
Comparison 19 Free ITN + undisclosed incentive for use vs. free ITN alone, Outcome 2 ITN use (Net mounted).
Comparison 20 Health framing vs. No framing marketing message, Outcome 1 Ownership (purchased experimental net).
Comparison 20 Health framing vs. No framing marketing message, Outcome 2 ITN use (net seen hanging after two months, if purchased).
Comparison 20 Health framing vs. No framing marketing message, Outcome 3 ITN used by children.
Comparison 20 Health framing vs. No framing marketing message, Outcome 4 ITN used by heads.
Comparison 21 Financial framing vs. No framing marketing message, Outcome 1 Ownership (purchased experimental net).
Comparison 21 Financial framing vs. No framing marketing message, Outcome 2 ITN use (net seen hanging after two months, if purchased).
Comparison 21 Financial framing vs. No framing marketing message, Outcome 3 ITN used by children.
Comparison 21 Financial framing vs. No framing marketing message, Outcome 4 ITN use by heads.
Comparison 22 Voucher given to female head vs. voucher given to both heads jointly, Outcome 1 Ownership (measured by purchased experimental net).
Comparison 22 Voucher given to female head vs. voucher given to both heads jointly, Outcome 2 ITN use (net seen hanging after 2 months, if purchased).
Comparison 22 Voucher given to female head vs. voucher given to both heads jointly, Outcome 3 ITN used by children.
Comparison 22 Voucher given to female head vs. voucher given to both heads jointly, Outcome 4 ITN used by heads.
Comparison 23 Voucher given to male head vs. voucher given to both heads jointly, Outcome 1 Ownership (purchased experimental net).
Comparison 23 Voucher given to male head vs. voucher given to both heads jointly, Outcome 2 ITN used (net seen hanging after 2 months, if purchased).
Comparison 23 Voucher given to male head vs. voucher given to both heads jointly, Outcome 3 ITN used by children.
Comparison 23 Voucher given to male head vs. voucher given to both heads jointly, Outcome 4 ITN used by heads.
Comparison 24 Verbal commitment to purchase ITN vs. no verbal commitment, Outcome 1 Ownership (purchased experimental net).
Comparison 24 Verbal commitment to purchase ITN vs. no verbal commitment, Outcome 2 ITN used (net seen hanging after 2 months).
Comparison 24 Verbal commitment to purchase ITN vs. no verbal commitment, Outcome 3 ITN used by children.
Comparison 24 Verbal commitment to purchase ITN vs. no verbal commitment, Outcome 4 ITN used by heads.
| Cost, education, and social marketing interventions to increase ITN ownership and use for malaria prevention | ||||
| Patient or population: Adults (including pregnant women) and children | ||||
| Outcomes | Impact | No of Participants | Quality of the evidence | Comments |
| Distributing ITNs free compared to making ITNs available for purchase through different mechanisms | ||||
| ITN ownership among pregnant women, adults and children | Free ITN distribution probably increases the number of pregnant women, adults and children who own ITNs compared to providing subsidized ITNs or ITNs offered at full market price.1 | 5090 (5 studies)2 | ⊕⊕⊕⊝ moderate certainty3 | Dupas 2009 noted that an increase in price from no cost to 1 USD led to a 35% drop in take‐up; and a 25% drop as price increased from 1 USD to 2 USD.4 |
| Appropriate use | Free ITN distribution probably leads to little or no difference in rates of usage of ITNs compared to providing subsidized ITNs or ITNs offered at full market price. | 8837 (4 studies)5 | ⊕⊕⊕⊝moderate certainty6 | |
| Education about appropriate ITN use compared with no ITN use education | ||||
| ITN use by adults (any ITN use) | May increase the number of adults using ITNs (including sleeping under ITNs). | 889 | ⊕⊕⊕⊝ | |
| ITN use by children under 5 | May increase the number of children under 5 years old using ITNs (including sleeping under ITNs). | 11,748 | ⊕⊕⊝⊝ | |
| Providing incentives to encourage ITN use compared to no incentives | ||||
| Use (net mounted) | Providing incentives to encourage ITN use probably leads to little or no difference in ITN use compared to those who did not receive an incentive. | 519 (1 study)11 | ⊕⊕⊕⊝ | |
| Adverse events | Not reported. | |||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||
| GRADE Working Group grades of evidence | ||||
| Adverse events were not reported in the studies. | ||||
| 1One study provided free ITNs to pregnant women, subsidized ITNs and social marketing to the community and compared this to control communities with access to subsidized ITNs and social marketing (Muller 2008). The second study provided women attending prenatal clinics with free ITNs , KES 10, KES 20, or KES 40 (Cohen 2010). 2 The studies included in this outcome are Cohen 2010, Dupas 2009, Fink 2012, Muller 2008, and Tarozzi 2011. Cohen 2010 included 424 participants and the remainder of the studies reported the number of households (4666 households). 3Baseline imbalances for most variables in the Muller 2008 study and some outcomes mentioned in the protocol were not reported in the final study. The Cohen 2010 study has small sample sizes in each of the 4 groups. Unclear ROB. Baseline characteristics of study participants not described and some mismanagement (leakage) of ITNs. The Dupas 2009 study had small samples sizes in each price group and unclear ROB. The Tarozzi 2011 study had unclear method of randomization and the intervention and control clients may have different characteristics. Allocation concealment was not described in Fink 2012. Some baseline differences between groups (fewer sleeping spaces in the control group, fewer ITNs at baseline in the free group). 4Dupas 2009 randomly assigned households to a subsidy level for ITNs (40% to 100%). ITN cost ranged from free to KES 300 (USD 4.62). Households received a voucher to obtain their net at the randomly assigned price. They were also assigned a "marketing" group (health vs. financial framing vs. none), a "commitment" group, and a "targeting" group (female head of household, male head, or both) (Dupas 2009). 5The included studies are Cohen 2010, Dupas 2009, Fink 2012, and Tarozzi 2011. Cohen included 259 participants and the remaining studies included 9968 households. 6Downgraded because of inconsistency. 7 Included studies are Amoran 2012 and Krezanoski 2010. The latter compared education with incentives vs no education or incentives. The number of participants reflects the number of households since these studies measured use at the household level. 8Baseline imbalances in the Amoran 2012 study (knowledge about appropriate ITN mounting was higher in the intervention group at baseline). 9Included studies are De La Cruz 2009, Deribew 2012, and Keating 2012. The number of participants reflects the number of households since these studies measured use at the household level. 10Baseline imbalances in all three studies in which ITN use was higher in the intervention groups. Inconsistency between studies (De La Cruz 2009; Deribew 2012; Keating 2012). Deribew 2012 is a CBA. 11The included study is Krezanoski 2010. 12Single study with small sample size (Krezanoski 2010). | ||||
|
| ITN delivery mechanisms | Appropriate ITN use interventions | |||||||
| Study overview | Channel | Duration | Cost to User | Choice of type and time | Sector | Channel | Duration | Type of intervention | Sector |
| AMORAN 20121 | ‐‐ | ‐‐ | ‐‐ | ‐‐ | ‐‐ | Community | Single | Education (provided to nursing mothers) | Civil society |
| COHEN 20102 | Routine Service | Single | Free, Subsidized (90% to 100%) | No choice of ITN type; | Public | ‐‐ | ‐‐ | ‐‐ | ‐‐ |
| DE LA CRUZ 20093 | ‐‐ | ‐‐ | ‐‐ | ‐‐ | ‐‐ | Community (during bank meetings) | Single | Education | Civil society (NGO Freedom from Hunger (FFH)) |
| DERIBEW 20124 | Unclear (ITNs provided by UNICEF but delivery channel unclear) | Single | Free | No choice of ITN type; | Unclear whether delivered by members of the study team or the trained village residents | Civil society (Community members received training of trainers then gave training to heads of households in the intervention villages) | Single | Education (tailored training of household heads) | Civil society |
| DUPAS 20095 | Community (voucher given during house‐to‐house visit); | Single | Free, Subsidized (40% to 100%) | No choice of ITN type; | Commercial | Community (house‐to‐house visit) | Single | Education | Civil society (study personnel) |
| FINK 20126 | Other (research project staff) | Single (study campaign) | Free, partially subsidized (50%) for loan group, and market price for controls | No choice of ITN type; Time unclear | Civil society (research project) and private (cotton company) | ‐‐ | ‐‐ | ‐‐ | ‐‐ |
| KEATING 20127 | Other (Universal ITN delivery in rural areas provided by National Malaria Control Center and PATH Malaria Control and Evaluation Partnership in Africa) | ‐‐ | ‐‐ | ‐‐ | ‐‐ | Community | Single (study campaign) | Education (community health workers) | Civil Society and public (PATH Malaria Control and Evaluation Partnership in Africa and the Zambian Ministry of Health) |
| KREZANOSKI 20108 | Community (voucher given during house‐to‐house visit); | Single | Free (coupons) | No choice of ITN type; | Civil society (NGO distribution site) | Other (ITNs study team site in the town) | Single | Education | Civil society (NGO Population Services International ‐ PSI) |
| MULLER 20089 | Community | Unclear (possibly free ITNs in prenatal clinics and subsidized ITNs available in stores after the study campaign) | Free (prenatal clinics); subsidized (local retailers) | No choice of ITN type; Time ‐ unclear (subsidized and free ITNs possibly available and after the study) | Public (prenatal clinics); Commercial (local retailers) | Community | Single | Education (Information, Education and Communication (IEC activities)); publicity (radio and television messages, poster exhibition, community‐based information) | Civil society (NGO Population Services International ‐ PSI) |
| TAROZZI 201110 | Community | Single | Free, Market price | Limited choice of ITN type (choice of size; | Civil society | Community | Single | Education | Civil society (NGOBharat Integrated Social Welfare Agency ‐ BISWA) |
| 1.Intervention: a one day educational program based on the national malaria control program provided to nursing mothers. Comparison: households selected from a different town receiving no intervention. 2. 20 prenatal clinics were assigned to different subsidy levels: 3.Intervention: Malaria education 4.Intervention: Training of heads of households (education with posters, manuals and demonstrations on appropriate long‐lasting (LL) ITN use); Free LLITN; Monthly monitoring of appropriate use and malaria occurrence with appropriate LLITN use training; Three times a year mass blood examination for anemia and malaria of children under five and pregnant women 5.Intervention: Households were assigned to 6.Intervention: In the free group, households could receive one ITN for each sleeping space. In the loan group, households could get ITNs at 50% subsidized cost with repayment due at the end of the harvesting season. The maximum number of ITNs each household could receive was restricted to the number of sleeping spaces in the household. Comparison: ITNs for sale at market price. 7.Intervention: Community‐based interpersonal communication intervention delivered through community health workers (CHWs). CHWs provided information about malaria transmission, prevention, and ITNs. 8. Intervention: Voucher for an ITN and undisclosed "prize" promised for appropriate use; 9.Intervention 1: Access to subsidized ITNs + free ITNs available to pregnant women through prenatal clinics + social marketing;Interveniton 2: Access to subsidized ITNs + social marketing 10.Intervention: 1. Microlender BISWA offered contracts for the purchase of ITNs and re‐treatments (ITN price was not subsidized); | |||||||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased net) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 Use (ITN seen hanging after 2 months, if purchased) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 4 ITN used by adults Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased net) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 Use (ITN seen hanging after 2 months, if purchased) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 4 ITN used by adults Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased net) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 Use (ITN seen hanging after 2 months, if purchased) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 4 ITN used by adults Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased net) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 Use (ITN seen hanging after 2 months, if purchased) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 4 ITN used by adults Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased net) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 Use (ITN seen hanging after 2 months, if purchased) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 4 ITN used by adults Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 ITN ownership (purchased net) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (measured as a share of prenatal clients who acquired program ITN) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITNs use (self reported at follow‐up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 3 ITN use (net seen hanging at follow‐up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (measured as a share of prenatal clients who acquired program ITN) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITNs use (self reported at follow‐up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 3 ITN use (net seen hanging at follow‐up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (measured as a share of prenatal clients who acquired program ITN) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITNs use (self‐reported at follow‐up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 3 ITN use (net seen hanging at follow‐up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 ITN ownership Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 No of households with at least one intervention ITN Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 Number of households with at least one ITN Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 Last night of bednet (%) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Nets owned per household (measured as nets owned) Show forest plot | 2 | 1489 | Std. Mean Difference (IV, Random, 95% CI) | 0.69 [0.39, 0.99] |
| 2 Use (nets used per household, seen at follow‐up) Show forest plot | 1 | Mean Difference (IV, Random, 95% CI) | Subtotals only | |
| 3 Usual ITN use in peak season Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 4 Slept under a net the night before the survey Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 5 Malaria positive (total) Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 6 Anaemia (Hb< 11g/dL) Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Nets owned per household (measured as nets owned) Show forest plot | 2 | 1507 | Std. Mean Difference (IV, Random, 95% CI) | 0.29 [‐0.06, 0.63] |
| 2 Use (nets used per household, seen at follow‐up) Show forest plot | 1 | Mean Difference (IV, Random, 95% CI) | Subtotals only | |
| 3 Usual ITN use in peak season Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 4 Slept under a net the night before the survey Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 5 Malaria positive (total) Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 6 Anaemia (Hb< 11g/dL) Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Nets owned per capita (measured as nets owned) Show forest plot | 2 | 1554 | Std. Mean Difference (IV, Random, 95% CI) | 0.37 [0.27, 0.47] |
| 2 Use (nets used per household, seen at follow‐up) Show forest plot | 1 | Mean Difference (IV, Random, 95% CI) | Subtotals only | |
| 3 Usual ITN use in peak season Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 4 Slept under a net the night before the survey Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 5 Malaria positive (total) Show forest plot | 2 | Odds Ratio (Random, 95% CI) | 1.07 [0.96, 1.20] | |
| 6 Malaria positive (children under 15) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 7 Anaemia (Hb< 11g/dL) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Owns at least one ITN Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 Children under 5 sleeping under ITN Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 ITN utilization by under‐five children at 6 months follow up Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 ITN utilization by under‐five children at 12 months Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 Had fever in last 2 weeks (self reported at 6 months) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 4 Had fever in last 2 weeks (self reported at 12 months) Show forest plot | 1 | Risk Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Any ITN use in house (at follow up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITN use among children <5 (at follow‐up) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Prevalence of ITN use (ever use ITN) Show forest plot | 1 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 ITN ownership Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 1.1 Follow‐up at one month | 1 | 519 | Risk Ratio (Random, 95% CI) | 1.0 [0.99, 1.01] |
| 1.2 Follow‐up at 6 month | 1 | 519 | Risk Ratio (Random, 95% CI) | 0.99 [0.97, 1.01] |
| 2 ITN use (Net mounted) Show forest plot | 1 | Risk Ratio (Random, 95% CI) | Subtotals only | |
| 2.1 Follow up at one month | 1 | 519 | Risk Ratio (Random, 95% CI) | 1.10 [0.94, 1.28] |
| 2.2 Follow‐up at 6 months | 1 | 519 | Risk Ratio (Random, 95% CI) | 1.00 [0.95, 1.07] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased experimental net) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITN use (net seen hanging after two months, if purchased) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 4 ITN used by heads Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased experimental net) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITN use (net seen hanging after two months, if purchased) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 4 ITN use by heads Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (measured by purchased experimental net) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITN use (net seen hanging after 2 months, if purchased) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 4 ITN used by heads Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased experimental net) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 2 ITN used (net seen hanging after 2 months, if purchased) Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| 4 ITN used by heads Show forest plot | 1 | Odds Ratio (Random, 95% CI) | Subtotals only | |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Ownership (purchased experimental net) Show forest plot | 1 | Odds Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 2 ITN used (net seen hanging after 2 months) Show forest plot | 1 | Odds Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 3 ITN used by children Show forest plot | 1 | Odds Ratio (M‐H, Random, 95% CI) | Subtotals only | |
| 4 ITN used by heads Show forest plot | 1 | Odds Ratio (M‐H, Random, 95% CI) | Subtotals only | |
