Vaccination Coverage Among Preschool Children in Germany: Trends, Regional Disparities, and Determinants from School Enrolment Examinations in Two Metropolitan Regions

Background. Vaccinations are highly effective in preventing infectious diseases, which otherwise present a serious challenge to the health of individuals and public health. To identify potential gaps in vaccination coverage, we examined childhood vaccination levels in Frankfurt am Main (FFM) and the Rhein Neckar district (including Heidelberg city, RNHD) prior to, during and following the COVID-19 pandemic. Moreover, we explored various factors that appear to contribute to lower vaccination levels in specific communities in either or both locations. The results are intended to guide strategies for designing and improving vaccination services for specific groups in local health settings. Methods. A retrospective analysis was conducted to examine the vaccination rates of children in Frankfurt am Main and the Rhein Neckar district (including Heidelberg city) by using anonymized data from school entry examinations spanning the years 2017 to 2024. Data pre-processing, analysis, and visualization were performed using R (5.4.2). Frequencies and percentages were calculated for sociodemographic and vaccination rates (the completeness of the vaccination schedule recommended by STIKO for children). Multivariate logistic regression was performed to determine factors with a significant impact on vaccination uptake. Results. Multinomial logistic regression with ‘measles-only’ (Measles) as the reference category revealed distinct predictor patterns across vaccination levels. In both regions, children who completed preventive medical check-ups had higher odds of completing the schedule of vaccination plus at least one additional vaccine (ScheduledPlus) versus, measles-only vaccination. In RNHD, children from Eastern European language families and low- and medium-social-status backgrounds showed higher odds of completing the scheduled vaccinations without the recently introduced rotavirus vaccination (ScheduledNotRota), versus measles-only vaccination. In FFM, strong interaction effects were observed between medical examination completion and migration background, with children from non-German birthplaces showing dramatically reduced odds of complete vaccination when preventive care was incomplete. Discussion. The proportion of children with a complete vaccination status remained stable over the study period in both locations, with no evidence of post-pandemic decline. Nevertheless, this stability masks important heterogeneity in vaccine coverage patterns across sociodemographic groups. Systematic identification and modeling of interactions between nationality, parental employment, and healthcare utilization tell a compelling “double jeopardy” story that the effects of these risk factors are not additive but synergistic. Regular medical check-ups remain an important factor in ensuring high vaccination coverage among children until they start school and underscore the justification for such established preventive care programs. A nuanced understanding, however, is crucial for moving beyond simplistic, one-size-fits-all public health messaging.