Do Regional Social and Material Characteristics Influence Human Papillomavirus (HPV) Vaccine Decision-Making? The Ontario Grade 8 HPV Vaccine Cohort Study

Abstract

Aims: Although social and material characteristics are known determinants of health behaviours, there is no information on whether these factors influence human papillomavirus (HPV) vaccine decision-making. Moreover, few studies consider the potentially important influence of regional-level factors on HPV vaccine use. The objective of this study was to evaluate regional social and material characteristics as potential determinants of HPV vaccine refusal. Study Design: Population-based retrospective cohort. Methodology: Population-based administrative health and immunization databases were used to identify girls eligible for Ontario’s Grade 8 HPV vaccination program during the 2007/08-2010/11 program years. A cohort member was classified as a ‘refuser’ if she received no doses of the vaccine. Regional-level (i.e., health unit-level) social and material characteristics potentially associated with HPV vaccine decision-making were derived from the 2006 Canadian Census. The association between a girl’s environment and vaccine refusal was assessed using generalized estimating equations with a binomial distribution and a log link to estimate a population-average effect. Results: We identified a cohort of 144,047 girls, almost half (49.3%) of whom refused HPV vaccination. Overall refusal ranged from 42-60% across health units. For the majority of health units, refusal was highest in the first program year. While most regional-level factors were not strongly associated with HPV vaccine use, high regional deprivation was associated with low vaccine refusal (OR=0.86, 95% CI: 0.83, 0.89). Conclusions: Our findings of an association between high regional deprivation and low HPV vaccine refusal may be promising in terms of the health and economic benefits of this program. Future studies incorporating both individual- and regional-level determinants are needed to further elucidate the determinants of HPV vaccine refusal in the context of publicly funded, school-based programs.