Abstract
The HPV vaccination program in Brazil, introduced in 2014 for girls and 2017 for boys, aims to reduce HPV-related diseases, including anogenital warts (AGW) and high-grade cervical intraepithelial neoplasia (CIN). This descriptive ecological study evaluated the program's impact on hospitalizations for AGW and high-grade-CIN using interrupted time series analysis of data from the Brazilian Hospital Information System from 2011 to 2019. From 2011 to 2019, there were 4,312 AGW hospitalizations among females, 7,295 AGW hospitalizations among males, and 84,306 hospitalizations for high-grade CIN. Following the implementation of the HPV vaccination program, significant reductions in hospitalizations for AGW and high-grade CIN were observed, particularly in the targeted 15-19-year-old age group. In this group, the median number of hospitalizations prevented was 174 (95% CI: 154-193) for AGW among females, 116 (95% CI: 86-147) for AGW among males, and 217 (95% CI: 94-339) for high-grade CIN, with strong model fits. Downward trends were also noted in older age groups, though with poorer model fits. The HPV vaccination program has significantly reduced hospitalizations for AGW and high-grade CIN in Brazil, particularly among the targeted age group. Local evidence of early disease benefits reinforces the importance of HPV immunization in reducing the burden of HPV-related diseases and support expanding vaccination efforts for broader public health benefits. Reductions of AGW and high-grade CIN in older age groups may reflect indirect vaccination effects and treatment strategies, respectively.