Determinants of HPV vaccination intentions among Dutch girls and their mothers: a cross-sectional study

BACKGROUND: The Dutch government recently added universal Human Papilloma Virus (HPV) vaccination for 12-year-old girls to the existing national immunization program. The participation rate for the initial catch-up campaign for girls aged 13 to 16 years in 2009 was lower (47%) than expected (70%). To inform future HPV information campaigns, this paper examines the social and psychological determinants of the HPV vaccination intentions of girls aged 13 to 16 years and their mothers who were targeted by the Dutch catch-up campaign of 2009. METHODS: A random sample of girls and their mothers was chosen from the Dutch vaccination register and received a letter inviting them to participate (n = 5,998 mothers and daughters). In addition, a random sample was recruited via an online panel by a marketing research company (n = 650 mothers; n = 350 daughters). Both groups were asked to complete a web-based questionnaire with questions on social demographic characteristics, social-psychological factors and HPV vaccination intention. Backward linear regression analyses were conducted to examine which social-psychological factors were most dominantly associated with vaccination intention. RESULTS: Data from 952 mothers (14%) and 642 daughters (10%) were available for the intended analyses. The contribution of social demographic variables to the explained variance of HPV vaccination intention was small but significant for mothers (DeltaR(2) = .01; p = .007), but not significant for daughters (DeltaR(2) = .02; p = .17) after controlling for HPV vaccination uptake and the sample. In addition, social-psychological determinants largely contributed to the explained variance of HPV vaccination intention of mothers (DeltaR(2) = .35; p < .001) and daughters (DeltaR(2) = .34; p < .001). Attitudes, beliefs, subjective norms and habit strength were significantly associated with participants' HPV vaccination intentions. CONCLUSIONS: Because of the large contribution of social-psychological variables to the explained variance of HPV vaccination intentions among the mothers and daughters, future communication strategies targeting HPV vaccination uptake should address attitudes, beliefs, subjective norms and habit strength. There is a need for longitudinal research to confirm the causality of the association between these determinants and HPV vaccination behavior indicated by this study