Marked increase in measles vaccination coverage among young adults in Switzerland: a campaign or cohort effect?

OBJECTIVES: To evaluate the impact of the Swiss measles elimination strategy-including a mass media campaign-on vaccination coverage and awareness among young adults aged 20-29 years.

METHODS: Comparison of the results of two cross-sectional population surveys in 2012 and 2015.

RESULTS: Documented vaccination coverage increased from 77 to 88% for two doses of measles vaccine. Major determinants of complete vaccination were survey year, birth cohort, sex and the absence of prior measles disease. If birth cohort and prior history of measles disease are included as factors in a multivariate model, the difference between 2012 and 2015 vanishes.

CONCLUSIONS: The marked increase in complete measles vaccination coverage is due to a cohort effect, owing to the introduction of the second dose of vaccine in 1996. Most of the vaccinations were administered before the national strategy was implemented and vaccination catch-ups did not increase during the campaign in young adults. Nevertheless, this study provides evidence of an improvement in the awareness of measles and measles vaccination in young adults, which may result in an impact on measles vaccination coverage in the near future.