Abstract for: A System Dynamics Model of HPV Vaccinations Among Adolescent Boys in New York State

Human Papillomavirus (HPV) remains the most prevalent sexually transmitted infection in the U.S. and is the cause of several types of preventable cancers. Despite the high efficacy and safety of early vaccination, uptake among males remain lower than females, primarily due to delayed rollout and hesitancy. This study utilizes a system dynamics model to analyze the drivers of the HPV vaccine uptake among adolescent boys (ages 9-17) in New York State (excluding NYC) to identify high-leverage intervention points. We developed and calibrated a system dynamics model to simulate the interactions between parents, providers, and adolescents. The model categorizes parental hesitancy into three hesitancy levels and utilizes conveyor belts to model a discrete aging of adolescents from 9 to 17 years old. Calibration was performed using historical data (2008-2024) and hesitancy levels were estimated from public data. We test five strategies on the uptake of the HPV vaccine until 2032. The model demonstrated a strong fit to the historical vaccination data, revealing a steady upward trend in initiation. Simulation results indicate that a 25% increase in provider recommendations would result in a 6.23% increase in first-dose uptake and a 6.07% increase in series completion by 2032 compared to the base run. A combination of increasing provider recommendation and decreasing the delays in vaccinations showed the strongest effects. We believe this to be the first model that utilizes a system dynamics approach to explore HPV vaccine uptake among adolescents. Our findings suggest that targeting provider behavior is a high-leverage strategy for sustaining population-level protection and counteracting the negative impact of post-pandemic vaccine hesitancy and decreased uptake