Impact of HPV vaccination on cervical precancer and invasive cervical cancer twelve years after vaccine introduction in the Brazilian Public Health System.
This observational Brazilian analysis reports lower cervical precancer and invasive cervical cancer incidence after national HPV vaccine introduction among vaccine-eligible women, with heterogeneous reductions across regions and possible indirect protection in some non-eligible groups.
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This observational Brazilian analysis reports lower cervical precancer and invasive cervical cancer incidence after national HPV vaccine introduction among vaccine-eligible women, with heterogeneous reductions across regions and possible indirect protection in some non-eligible groups.
Research significance
The reported population-level associations support HPV vaccination as a plausible cancer-prevention strategy for children and adolescents; however, attributing the reductions—and possible indirect protection—specifically to vaccination remains an inference because the supplied observational comparison does not establish causality or exclude changes in screening, surveillance, or other temporal factors.
Source abstract
BACKGROUND: The national HPV vaccination program was introduced into the Brazilian public health system for children and adolescents in 2014. However, its population-level impact remains poorly characterized, particularly in the context of regional disparities. METHODS: We compared the incidence of cervical precancer and invasive cancer between the pre-vaccination period (2010-2012) and the post-vaccination period (2025) among screened women aged < 25 years (vaccine-eligible women) and ≥ 25 years (non-vaccine-eligible women) in Brazil and across its geographic regions. RESULTS: Among vaccine-eligible women, the incidence of CIN2 +, CIN3 +, and invasive cervical cancer was significantly lower in the post-vaccination period than in the pre-vaccination period in Brazil. Incidence rates were lower across all regions; however, statistically significant reductions in all three outcomes were observed only in the Southeast, South, and Midwest. In the Northeast, significant reductions were observed for CIN2 + and invasive cervical cancer, whereas no significant reductions were observed in the North. The reduction in invasive cervical cancer incidence was significantly greater than those observed for CIN2 + and CIN3 +. Among non-vaccine-eligible women, significant reductions were observed primarily for invasive cervical cancer. Nationally, reductions were observed among women aged 25-29 and 55-64 years. Regionally, reductions occurred in the Southeast among women aged 25-64 years, in the South among those aged 25-29 years, and in the Midwest among those aged 55-64 years. Significant reductions in CIN2 + and CIN3 + were limited to women aged 55-64 years in the Southeast and Midwest. In all other age groups, outcome and regions, incidence showed either significant increases or no statistically significant changes. CONCLUSIONS: Twelve years after the introduction of HPV vaccination, these findings support a population-level impact of HPV vaccination in Brazil and most regions among vaccine-eligible women. Among non-vaccine-eligible women, the findings suggest possible indirect protection, varying by outcome, age group and region.