Assessing sociodemographic disparities in HPV vaccine uptake among grade 6 and 9 students in the Vancouver Coastal Health region

To identify sociodemographic factors associated with HPV vaccine uptake in a universal, in-school HPV vaccination program, among grade 6 and 9 students in the regional health authority of Vancouver Coastal Health (VCH), British Columbia (BC), Canada during the 2021/22 school year. VCH operates within the southwest corner of the province of BC serving a mix of urban and rural regions. HPV vaccine is offered in school to all grade 6 students using a two-dose series, with catch up immunizations offered to students in grade 9. We conducted a cross-sectional study of grade 6 and 9 students enrolled in VCH schools for the 2021/22 school year, who also resided within the VCH region. We modelled the associations between sociodemographic explanatory variables (individual-level and group-level) and fully vaccinated outcome using a cross-classified (non-nested) multilevel model. Among the 17,939 students eligible, 74 % were fully vaccinated for HPV. Immunization coverage was associated with grade, geographic area of residence, school category, social and material deprivation. We demonstrated that grade modified the association between material deprivation and being fully vaccinated. Grade 9 students, including those residing in more materially deprived neighbourhoods, had substantially higher odds (OR 2.01 [95 % CI 1.08, 3.75]) of being fully vaccinated relative to grade 6 students in the least materially deprived neighbourhoods. Though publicly funded HPV vaccine is offered to all students in grade 6 and 9, in a space that maximizes programmatic access, sociodemographic factors associated with under-immunized populations were identified. This information can be leveraged for strategic targeting of resources to underimmunized schools or students to mitigate impacts. The repeat offering of HPV vaccine in an older grade (grade 9 in BC) is a key programmatic strategy to reach under-immunized populations and should be complemented by other creative approaches.