Drivers of HPV vaccination rates among adolescent dependents in the military health system

Background: Human papillomavirus (HPV) vaccination prevents several forms of cancer. HPV vaccination is inconsistent and little is known about rates of HPV vaccination among adolescents in the Military Health System (MHS). Objective: To estimate the drivers of variation in HPV vaccination among adolescent dependents of military service members. Design: Using 2007–2019 MHS Data Repository Data, we utilize a cohort study design to estimate Kaplan-Meier curves of vaccination rates and estimated the effect of parent factors (rank, service branch) and catchment area factors (average per capita spending and fraction of care purchased from the private sector). Further, we estimated the impact of multiple moves and how moving from catchment areas with low (or high) vaccination rates to catchment areas with high (or low) vaccination impacted subsequent HPV vaccination rates. Participants: We identified a sample of adolescent dependents of military service members who were continuously enrolled in TRICARE from ages 9 to 13, 15, or 17 depending on outcome; and who had not been vaccinated by age 11. Main Measures. Any HPV vaccination and up-to-date HPV vaccination. Key Results. HPV vaccination rates were lower among adolescents of parents with more senior rank. Adolescents moving from lower HPV vaccination rate catchment areas to higher HPV vaccination rate catchment areas were significantly more likely to become vaccinated emphasizing the importance of provider factors in explaining variation in HPV vaccination. Adolescents experiencing multiple moves were significantly (approximately 30 percentage points, p < 0.001) less likely to become vaccinated. Conclusions: Understanding successful approaches of high HPV vaccination catchment areas; and targeting interventions to families experiencing multiple moves during adolescence is critical to improving HPV vaccination within the MHS.