INTRODUCTION: Evaluating area-level inequalities in vaccination is critical for identifying target areas of community-based interventions. However, knowledge of inequalities in human papillomavirus (HPV) vaccination in Japan remains limited. We aim to investigate changes in inequalities in HPV vaccination by neighborhood-based socioeconomic status and medical access indicators in Osaka City. METHODS: Human papillomavirus vaccination data from April 2013 to March 2023 were provided by Osaka City. We calculated cumulative HPV vaccination uptake by the Areal Deprivation Index as a neighborhood-level socioeconomic indicator and the number of medical facilities providing HPV vaccine within a 500-m range of a representative point in each unit as a medical access indicator. The Slope Index of Inequality (SII) and the Relative Index of Inequality (RII) were used to assess absolute and relative inequality, respectively. RESULTS: Lower cumulative HPV vaccination uptake in 2022 was observed in more deprived areas (the percentages of least to most deprived areas: 23.2%, 21.8%, 21.1%, 21.1%, 20.6%) and lower access areas (the percentages of highest to lowest access areas: 22.3%, 21.8%, 20.9%). The inequalities in vaccination uptake between the most and least deprived areas were widened from 2013 to 2022 (SII: −0.5 to −3.0; RII: 0.8 to 0.6). The inequalities between the lowest and highest access areas were also widened from 2013 to 2022 (SII: −0.4 to −1.7; RII: 0.8 to 0.8). CONCLUSIONS/IMPLICATIONS: Widening inequalities in HPV vaccination by neighborhood-based socioeconomic and access indicators were observed. Further strategies, including social–ecological approaches, are needed to reduce inequalities in the uptake.
Oka et al. (2026) studied this question.