Sociodemographic and parental health factors associated with initiation of human papillomavirus vaccination among boys in a national free-of-charge program in Denmark

OBJECTIVE: Human papillomavirus (HPV) causes oropharyngeal, anal, and penile cancers in men. In 2019, HPV vaccination for boys was included in Denmark's free-of-charge childhood vaccination program. This study examines sociodemographic and parental health factors associated with HPV vaccine initiation among Danish boys.

METHODS: This nationwide, register-based cohort study included all boys living in Denmark and born July 2007-December 2010 (n = 113,519), representing the first eligible cohorts. Boys were followed up until December 2024, and vaccine initiation within 12 months after their 12th birthday was identified through national registers, which also provided sociodemographic factors and parental medical conditions. Logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) for associations with vaccine initiation.

RESULTS: Prevalence of HPV vaccine initiation was 79.5%. Uptake was lower among boys of immigrant origin (OR = 0.85; 95%CI: 0.79, 0.90) and those not living with both legal parents. Uptake was higher among boys from families with higher education (OR = 1.29; 95%CI: 1.23, 1.35), higher income (OR = 1.95; 95%CI: 1.85, 2.05), or a parental history of cancer or HPV-associated precancer (OR = 1.11; 95%CI: 1.06, 1.17).

CONCLUSIONS: Most eligible Danish boys initiate HPV vaccination. Social disparities persist despite universal free access, and key predictors of uptake were ethnicity, family structure, and socioeconomic status.