Skip to main content
Top
Published in: BMC Medicine 1/2020

01-12-2020 | Vaccination | Research article

Estimating the contribution of different age strata to vaccine serotype pneumococcal transmission in the pre vaccine era: a modelling study

Authors: Stefan Flasche, Marc Lipsitch, John Ojal, Amy Pinsent

Published in: BMC Medicine | Issue 1/2020

Login to get access

Abstract

Background

Herd protection through interruption of transmission has contributed greatly to the impact of pneumococcal conjugate vaccines (PCVs) and may enable the use of cost-saving reduced dose schedules. To aid PCV age targeting to achieve herd protection, we estimated which population age groups contribute most to vaccine serotype (VT) pneumococcal transmission.

Methods

We used transmission dynamic models to mirror pre-PCV epidemiology in England and Wales, Finland, Kilifi in Kenya and Nha Trang in Vietnam where data on carriage prevalence in infants, pre-school and school-aged children and adults as well as social contact patterns was available. We used Markov Chain Monte Carlo methods to fit the models and then extracted the per capita and population-based contribution of different age groups to VT transmission.

Results

We estimated that in all settings, < 1-year-old infants cause very frequent secondary vaccine type pneumococcal infections per capita. However, 1–5-year-old children have the much higher contribution to the force of infection at 51% (28, 73), 40% (27, 59), 37% (28, 48) and 67% (41, 86) of the total infection pressure in E&W, Finland, Kilifi and Nha Trang, respectively. Unlike the other settings, school-aged children in Kilifi were the dominant source for VT infections with 42% (29, 54) of all infections caused. Similarly, we estimated that the main source of VT infections in infants are pre-school children and that in Kilifi 39% (28, 51) of VT infant infections stem from school-aged children whereas this was below 15% in the other settings.

Conclusion

Vaccine protection of pre-school children is key for PCV herd immunity. However, in high transmission settings, school-aged children may substantially contribute to transmission and likely have waned much of their PCV protection under currently recommended schedules.
Appendix
Available only for authorised users
Literature
3.
go back to reference International Vaccine Access Center - Johns Hokins Bloomberg School of Public Health. Global PCV introduction status [Internet]. 2015 [cited 2016 Sep 5]. Available from: http://view-hub.org/viz/. International Vaccine Access Center - Johns Hokins Bloomberg School of Public Health. Global PCV introduction status [Internet]. 2015 [cited 2016 Sep 5]. Available from: http://​view-hub.​org/​viz/​.
7.
go back to reference Weinberger DM, Malley R, Lipsitch M. Serotype replacement in disease after pneumococcal vaccination. Lance. 2011;378:1962–73.CrossRef Weinberger DM, Malley R, Lipsitch M. Serotype replacement in disease after pneumococcal vaccination. Lance. 2011;378:1962–73.CrossRef
12.
go back to reference Goldblatt D, Southern J, Andrews NJ, Burbidge P, Partington J, Roalfe L, et al. Pneumococcal conjugate vaccine 13 delivered as one primary and one booster dose (1 + 1) compared with two primary doses and a booster (2 + 1) in UK infants: a multicentre, parallel group randomised controlled trial. Lancet Infect Dis. 2017;3099(17):1–9 Available from: http://linkinghub.elsevier.com/retrieve/pii/S1473309917306540. Goldblatt D, Southern J, Andrews NJ, Burbidge P, Partington J, Roalfe L, et al. Pneumococcal conjugate vaccine 13 delivered as one primary and one booster dose (1 + 1) compared with two primary doses and a booster (2 + 1) in UK infants: a multicentre, parallel group randomised controlled trial. Lancet Infect Dis. 2017;3099(17):1–9 Available from: http://​linkinghub.​elsevier.​com/​retrieve/​pii/​S147330991730654​0.
18.
go back to reference World Health Organization. Meeting of the Strategic Advisory Group of Experts on immunization, October 2017 – conclusions and recommendations. Wkly Epidemiol Rec. 2017;48(92):729–48. World Health Organization. Meeting of the Strategic Advisory Group of Experts on immunization, October 2017 – conclusions and recommendations. Wkly Epidemiol Rec. 2017;48(92):729–48.
32.
go back to reference Hammitt LL, Akech DO, Morpeth SC, Karani A, Kihuha N, Nyongesa S, et al. Population effect of 10-valent pneumococcal conjugate vaccine on nasopharyngeal carriage of Streptococcus pneumoniae and non-typeable Haemophilus influenzae in Kilifi, Kenya: findings from cross-sectional carriage studies. Lancet Global Health. 2014:e397–405 [cited 2014 Aug 7]. Available from: http://linkinghub.elsevier.com/retrieve/pii/S2214109X14702244. Hammitt LL, Akech DO, Morpeth SC, Karani A, Kihuha N, Nyongesa S, et al. Population effect of 10-valent pneumococcal conjugate vaccine on nasopharyngeal carriage of Streptococcus pneumoniae and non-typeable Haemophilus influenzae in Kilifi, Kenya: findings from cross-sectional carriage studies. Lancet Global Health. 2014:e397–405 [cited 2014 Aug 7]. Available from: http://​linkinghub.​elsevier.​com/​retrieve/​pii/​S2214109X1470224​4.
37.
go back to reference Lipsitch M, Abdullahi O, D’Amour A, Wen X, Weinberger DM, Tchetgen ET, et al. Estimating rates of carriage acquisition and clearance and competitive ability for pneumococcal serotypes in Kenya with a Markov transition mode. Epidemiology. 2012;23(4):1–10 [cited 2012 Mar 27]. Available from: http://www.ncbi.nlm.nih.gov/pubmed/22441543.CrossRef Lipsitch M, Abdullahi O, D’Amour A, Wen X, Weinberger DM, Tchetgen ET, et al. Estimating rates of carriage acquisition and clearance and competitive ability for pneumococcal serotypes in Kenya with a Markov transition mode. Epidemiology. 2012;23(4):1–10 [cited 2012 Mar 27]. Available from: http://​www.​ncbi.​nlm.​nih.​gov/​pubmed/​22441543.CrossRef
52.
go back to reference Dureau J, Kalogeropoulos K, Baguelin M. Capturing the time-varying drivers of an epidemic using stochastic dynamical systems. Biostatistics. 2013;14(3):541–55.PubMedCrossRef Dureau J, Kalogeropoulos K, Baguelin M. Capturing the time-varying drivers of an epidemic using stochastic dynamical systems. Biostatistics. 2013;14(3):541–55.PubMedCrossRef
56.
Metadata
Title
Estimating the contribution of different age strata to vaccine serotype pneumococcal transmission in the pre vaccine era: a modelling study
Authors
Stefan Flasche
Marc Lipsitch
John Ojal
Amy Pinsent
Publication date
01-12-2020
Publisher
BioMed Central
Keyword
Vaccination
Published in
BMC Medicine / Issue 1/2020
Electronic ISSN: 1741-7015
DOI
https://doi.org/10.1186/s12916-020-01601-1

Other articles of this Issue 1/2020

BMC Medicine 1/2020 Go to the issue