Has Their Son Been Vaccinated? Beliefs About Other Parents Matter for Human Papillomavirus Vaccine

The goal of this study was to determine if parents' beliefs about social norms of human papillomavirus (HPV) vaccination for sons were associated with knowledge of HPV, intention to vaccinate sons, or beliefs about side effects. A cross-sectional, survey-based study of parents with sons was performed in 2010. Fisher's exact tests were used to examine associations between demographics and responses about social norms. Multivariate logistic regression models examined beliefs about social norms of male HPV vaccination and primary outcomes. Few parents agreed that others were vaccinating sons (n = 31/267, 12%), including 1% responding strongly agree and 11% responding agree. Most parents, 52%, disagreed that others were vaccinating (40% disagree, 11% strongly disagree), and 37% chose prefer not to answer regarding others' vaccination practices. Hispanic parents and those with a high school education or less were significantly more likely to choose prefer not to answer than their respective counterparts regarding vaccination norms. In multivariate models, parents agreeing others were vaccinating sons had greater odds of having high knowledge of HPV (adjusted odds ratio [aOR] high vs low knowledge 3.15, 95% confidence interval [CI] 1.13, 8.77) and increased intention to vaccinate sons (n = 243, aOR = 4.41, 95% CI = 1.51, 12.89). Beliefs about side effects were not significantly associated with beliefs about social norms. Parents' beliefs about others' vaccination practices are important with regard to knowledge of HPV and intention to vaccinate sons. Studying how various public messages about HPV vaccine may influence normative beliefs could be relevant to improving vaccination coverage.