Why are older adults and individuals with underlying chronic diseases in Germany not vaccinated against flu? A population-based study

Older adults and individuals with underlying chronic diseases are at increased risk of developing influenza-related complications and are target groups for seasonal influenza vaccination in many countries. In Germany, an annual national information campaign is conducted to increase influenza vaccination uptake in the target groups. However, data are lacking on knowledge and attitudes toward influenza vaccination among older adults and those with chronic diseases. The present study aimed to (i) estimate influenza vaccination uptake for the 2012/13 and 2013/14 seasons, (ii) assess knowledge and attitudes about influenza vaccination, and (iii) identify factors associated with vaccination uptake in two risk groups.

Between March and June 2014, we conducted a nationwide cross-sectional survey in adults (≥18 years) living in Germany using computer-assisted telephone interviewing. We calculated weighted vaccination coverage rates in two at-risk groups. Group 1 comprised participants aged 18–59 years with underlying chronic diseases. Group 2 comprised participants aged 60+, irrespective of underlying disease. We used univariate and multivariable logistic regression analyses to identify associations between influenza vaccination uptake and sociodemographic characteristics, and to evaluate attitudes and knowledge.

In total, 1,519 interviews were conducted. Seasonal influenza vaccination uptake in people with underlying chronic diseases aged 18–59 years was 24 % in 2012/2013 and 23 % in 2013/2014. In older adults, uptake was 50 % and 49 % in 2012/13 and 2013/14 respectively. There were considerable vaccination-related knowledge gaps among respondents. For example, about half of the participants who aged ≥60 years and/or suffered from underlying chronic diseases believed that influenza vaccination could cause influenza. The most commonly stated reasons for not being immunized were mistrust of the vaccination (22 %) and the perception that influenza is not dangerous (21 %). For both groups, vaccination uptake was independently associated with sex, perceived severity of influenza, perceived vaccination effectiveness, and the perceived likelihood or severity of vaccination side effects. For older adults, additional factors influencing vaccination uptake were age, underlying chronic diseases, and recent advice through physician consultation.

Influenza vaccination coverage rates in Germany remain low. Individual perceptions regarding harms and benefits are crucial in the decision-making process. Communication strategies should focus on improving understanding and perception of personal risks arising from the disease and the vaccination.