The decrease in childhood vaccination coverage in the Netherlands from birth cohort 2008 to 2020 and its sociodemographic determinants

Introduction: To understand differences in vaccination coverage between population subgroups in the Netherlands over time, we studied sociodemographic factors associated with measles-mumps-rubella (MMR) and diphtheria-tetanus-pertussis-poliomyelitis (DTaP-IPV) vaccination. Methods: We conducted a national retrospective database study including children born in 2008-2020. Individual-level data-linkage allowed examination of associations of sociodemographic variables with MMR and DTaP-IPV vaccination status at 2 years of age. Coverage for each variable, stratified by birth cohort, was calculated. Multivariable Poisson regression assessed independent associations and changes in coverage over time. Results: MMR coverage decreased in all population subgroups (overall 95% to 89% in 2008 and 2020 cohorts), with more substantial declines in some groups. The multivariable analysis showed that Dutch children of non-Dutch origin, particularly those of Moroccan and Turkish origin showed more pronounced declines (-25% and -12% compared to children of Dutch origin in cohort 2020, respectively). Among children not attending day care and children living in larger families (≥4 children), a faster decline in coverage was observed compared to those attending day care and living in smaller families (both -12% in cohort 2020). Among children of self-employed mothers and children in the lowest income households, lower coverage was observed compared to children of mothers in employment and children in the highest income households (-8% and -7% in cohort 2020, respectively). Nearly identical trends were observed for DTaP-IPV vaccination. Conclusion: Our study reveals a significant decline in childhood vaccination coverage in the Netherlands, with increasing disparities between sociodemographic groups. This is crucial for prioritising vaccination efforts to protect public health equitably.