School vaccination programmes to increase HPV vaccination coverage - Experiences from Bremen, Germany.

Germany primarily relies on a practice-based, opportunistic immunisation system. Despite the introduction of the Human papillomavirus (HPV) vaccine into the German vaccination schedule in 2007, coverage remains low. International experience suggests that school-based vaccination can increase HPV coverage. Therefore, in 2013/14 Bremen's public health department offered HPV vaccinations within a school programme, targeting all 8th-graders. We aimed to evaluate the programme, with a focus on vulnerable groups. In a retrospective cohort design, we analysed vaccination status and uptake among all 8th-graders from 2015/16 to 2018/19 (girls) and 2022/23 (girls and boys). Sub-analyses were based on the School Social Index (SSI), which ranges from 1 (higher socio-economic position, SEP) to 5 (lower SEP), considering factors like poverty, migration, and living environment. The study included 13,550 students from 1,440 classes in 56 schools. Among previously unvaccinated students, 26-35 % of girls and 39 % of boys annually accepted and received the school-based HPV vaccination. Uptake was higher among students from lower as compared to higher SEP schools (SSI 5: 37 % vs. SSI 1: 30 %, p = 0.022). Vaccine uptake among unvaccinated students remained stable over time, with one-third receiving at least one HPV vaccination at school. The remaining two-thirds of unvaccinated did not make use of the vaccination offer at school. It needs to be investigated if this is possibly due to vaccine hesitancy or a preference for practice-based vaccinations. While school vaccination programmes can improve uptake, implementing a nationwide programme in Germany will be challenging and may not address all existing major uptake barriers.