HPV vaccination initiation among preadolescents in Veneto, Italy: associations with chronic conditions and socioeconomic disadvantage

BACKGROUND: Identifying population groups with lower human papillomavirus (HPV) vaccination uptake is essential for developing targeted public health interventions. This study examined whether chronic conditions and sociodemographic factors were associated with HPV vaccination initiation among preadolescents in the Veneto Region of Italy. METHODS: We conducted a retrospective cohort study using data from Pedianet, an Italian primary-care pediatric database. The study included children born between 2008 and 2011 who were followed between 9 and 12 years of age. Vaccination initiation was defined as receipt of at least one HPV vaccine dose from the ninth birthday to the day before the thirteenth birthday. Associations with sex, birth cohort, selected chronic conditions, disability, income-based healthcare exemption, and pediatric healthcare utilization were assessed using multivariable multilevel logistic regression, with a random intercept for family pediatrician. RESULTS: Among 19,245 children followed by 93 pediatricians, 53.6% received at least one HPV vaccine dose. Asthma was associated with higher odds of vaccination initiation (adjusted odds ratio [aOR] 1.36; 95% confidence interval [CI] 1.12-1.67), whereas disability (aOR 0.71; 95% CI 0.58-0.88), income-based healthcare exemption (aOR 0.81; 95% CI 0.76-0.86), and male sex (aOR 0.79; 95% CI 0.74-0.84) were associated with lower odds of initiation. Associations with receipt of two HPV vaccine doses within the same age window were broadly consistent with those for initiation. CONCLUSIONS: HPV vaccination initiation was associated with health-related and sociodemographic factors. Lower uptake among children with administratively recognized disability, those with income-based healthcare exemptions, and boys identifies groups that may benefit from targeted vaccination support. Further research should clarify the barriers underlying these associations.