Association Between Internet Access and Human Papillomavirus (HPV) Vaccination Coverage in Brazilian Municipalities: An Ecological Study

Background/Objectives: Human Papillomavirus (HPV) vaccination is the primary strategy for preventing HPV-related cancers, yet vaccination coverage (VC) remains uneven worldwide. Internet access may affect vaccination adherence, but its relationship with HPV VC at the population level is poorly understood. Therefore, we aim to describe the distribution of HPV VC and its association with household internet access across Brazilian municipalities and macro-regions, by sex and year. Methods: This ecological study examined the association between household internet access and HPV VC among girls and boys aged 9 to 14 years in Brazilian municipalities between 2022 and 2024. Two analytical approaches were used: (1) Categorical: both variables were dichotomized by their national medians, and prevalence ratios (PR) were estimated by Poisson regression with robust variance; (2) Continuous: VC was modelled in percentage points (p.p.) and internet access in 10-percentage-point increments, using linear regression with robust variance, for all municipalities and stratified by the five Brazilian macro-regions. Models were adjusted for sociodemographic and contextual variables. Results: A total of 5560 municipalities were included. HPV VC was consistently higher among girls, with medians between 83.5% and 85.2% over the three-year period, than among boys, between 51.9% and 73.6%. The median proportion of internet access was 81.0%, and municipalities classified as having high internet access ranged from about 21.0% in the Northeast to 73.4% in the Central-West. In the categorical approach, municipalities with high internet access showed a higher prevalence of high VC only in 2024, among girls (PR 1.09, 95% CI 1.02–1.15) and boys (PR 1.08, 95% CI 1.02–1.15). In the continuous approach, each 10-p.p. increase in internet access was associated with an increase in VC of 0.59 p.p. among girls in 2023 (95% CI 0.12–1.06) and 0.81 p.p. in 2024 (95% CI 0.37–1.25), and of 0.76 p.p. among boys in 2022 (95% CI 0.19–1.33), 0.86 p.p. in 2023 (95% CI 0.25–1.46) and 1.04 p.p. in 2024 (95% CI 0.50–1.58). Stratified analyses showed positive associations in the North and South, and inverse associations among boys in the Southeast region of Brazil. Conclusions: Municipalities with higher internet access showed higher HPV VC, although the association varied across years, sex, and macro-regions. These findings highlight differences in HPV vaccination coverage according to municipal levels of household internet access.