Exploring variation in human papillomavirus vaccination uptake: multi-level spatial analysis
BackgroundUnderstanding the factors that influence human papillomavirus (HPV) vaccination uptake is critically important to design effective vaccination programmes. In Switzerland, completed HPV vaccination by age 16 years among women ranges from 30 to 79% across 26 cantons (states). Our objective was to identify factors that are associated with the spatial variation in HPV vaccination uptake.\n\nMethods and findingsWe used data from the Swiss National Vaccination Coverage Survey 2009-2016 on HPV vaccination status ([≥]1 dose) of 14-17 year old girls, their municipality of residence and their nationality for 21 of 26 cantons (N=8,965). We examined covariates at municipality level: language, degree of urbanisation, socio-economic position, religious denomination, results of a vote about vaccination laws; and, at cantonal level, availability of school-based vaccination and survey period. We used a series of conditional auto regressive (CAR) models to assess the effects of covariates while accounting for variability between cantons and municipal-level spatial autocorrelation. In the best-fit model, school-based vaccination (adjusted odds ratio, OR: 2.51, 95% credible interval, CI: 1.77-3.56) was associated with increased uptake, while lower acceptance of vaccination laws was associated with lower HPV vaccination uptake (OR 0.61, 95% CI: 0.50-0.73). Overall, the covariates explained 88% of the municipal-level variation in uptake.\n\nConclusionsIn Switzerland, cantons play a prominent role in the variation in HPV vaccination uptake, especially through the provision of school-based vaccination delivery. HPV vaccination uptake is also strongly associated with inhabitants attitudes towards vaccination. To increase uptake, efforts should be made both to mitigate vaccination scepticism and to encourage school-based vaccination.