Losing ground at the wrong time: Trends in self-reported influenza vaccination uptake in Switzerland, Health Survey 2007–2017

Objectives

We studied time trends in seasonal influenza vaccination and associations with socioeconomic and health-related determinants in Switzerland, overall and in people aged ≥ 65 years.

Design

Three cross-sectional surveys.

Participants

Individuals who participated in the Swiss Health Surveys 2007, 2012, and 2017. We calculated the proportion reporting influenza vaccination in the last 12 months, and performed multivariable logistic regression analyses.

Results

The proportion of reporting a history of influenza vaccination overall was 31.9% (95% confidence intervals [95% CI] 31.4–32.4); and dropped from 34.5% in 2007 to 28.8% in 2017. The uptake of vaccination within the past 12 months was 16% in 2007 and similar in 2012 and 2017 (around 14%). In people with chronic disease, uptake dropped from 43.8% in 2007 to 37.1% in 2012 and to 31.6% in 2017 (p<0.001). In people aged ≥ 65 years, uptake dropped from 47.8% in 2007 to 38.5% in 2012 to 36.2% in 2017 (p<0.001). Similarly, a decrease in vaccine uptake was seen in people with poor self-reported health status (39.4%, 33.1%, and 27.0%). In logistic regression, self-reported vaccination coverage decreased in the 65 to 75 years old (adjusted odds ratio (aOR) aOR 0.56, 95% Cl 0.48–0.66 between 2007 and 2012; aOR 0.89, 95% CI 0.77–1.03). Uptake was positively associated with the ≥ 65 age group, living in French-speaking and urban areas, history of smoking, bad self-reported health status, private/semiprivate health insurance, having a medical profession, and having any underlying chronic disease. Use of any alternative medicine therapy was negatively associated with influenza vaccination (aOR 0.72, 95% CI 0.67–0.80).

Conclusion

Influenza vaccination coverage was low in older and chronically ill persons. Significant efforts are required in preparing for the flu season 2020/21 to reduce the double burden of COVID-19 and seasonal influenza. These efforts should include campaigns but also novel approaches using social media.

Strengths and limitations of this study

• Data analysis of the Swiss Health Survey 2007, 2012, and 2017 focussing on influenza vaccine uptake overall and in the age group ≥65 years in Switzerland.

• The Swiss Health Survey is a nationwide, representative survey that is repeated every five years using the same methodology.

• Analyses were weighted and adjusted for a wide range of important cofactors.

• We calculated percent of people reporting having been vaccinated and associations between vaccination status and socio-demographic and health-related factors.

• Influenza vaccination status is self-reported in the Swiss Health Survey and the reliability of the data not ascertained.