Maternal pertussis vaccination uptake and reasons for non-vaccination among pregnant women in the Netherlands: a 5-year retrospective cohort study.

INTRODUCTION: The maternal pertussis vaccination (MPV) was introduced in the Netherlands at the end of 2019. Despite its effectiveness, vaccine hesitancy remains, possibly influenced by factors such as age, education, employment, parity, native language, and country of birth. This study investigates associations between sociodemographic factors, MPV uptake, and reasons for declining the MPV among mothers of children born between January 2020 and March 2025. METHODS: This retrospective cohort study used data from a preventive Youth Health Care Center, including 17.513 biological mothers. Since the end of 2023, reasons for declining MPV have been recorded, with retroactive recall from January 2023, yielding 768 reasons from 728 mothers. Logistic regression analyses were conducted to examine associations between sociodemographic factors, MPV uptake, and reasons for not receiving the MPV. RESULTS: Higher MPV uptake was associated with higher maternal age (ORs ranges between 1.78 [95% CI 1.52-2.09] and 2.70 [95% CI 2.24-3.25]) and employed mothers (OR 2.55, 95% CI 2.26-2.87). Lower MPV uptake was associated with lower education (OR 0.41, 95% CI 0.37-0.46), parity (OR 0.61, 95% CI 0.55-0.68), and being born outside the Netherlands (varying ORs between countries/(parts of) continents). Most reasons were not associated with sociodemographic factors. However, mothers aged ≥41 years were more likely (OR 2.61, 95% CI 1.16-5.88) to decline MPV due to concerns about vaccination during pregnancy. Mothers whose native language was not Dutch or English more often cited that they did not receive (right) information (on time) from healthcare workers (ORs ranges between 2.19 [95% CI 1.10-4.34] and 2.96 [95% CI 1.19-7.37]). CONCLUSION: This study highlights not only how sociodemographic factors relate to MPV acceptance but also shows that reasons for MPV hesitancy cross through various sociodemographic groups. Findings offer new directions for targeted interventions to increase uptake and protect all newborns from pertussis.