Understanding divergent parental decisions: Declining pertussis vaccination during pregnancy while accepting infant immunisation-A qualitative study

Background: Pertussis vaccination during pregnancy (VdP) is around 90% effective in protecting infants against pertussis. Passive immunisation protects infants until they are old enough to receive active immunisation themselves. Over a quarter of Dutch infants participating in the National Immunisation Program have mothers who did not receive pertussis VdP. This study aimed to identify factors related to vaccination care that influenced mothers' decision not to receive the pertussis VdP, while accepting a pertussis vaccination for their infants. Methods: Semi-structured in-depth interviews were conducted with Dutch mothers, within six months postpartum, across four regions in the Netherlands: The Hague, Utrecht, and southern parts of the Dutch provinces Gelderland and Limburg. Interviews were analysed with the use of the Thematic Codebook Analysis method. Results: A total of 22 participants were interviewed. The participants were diverse in age (range: 23-41) and thirteen were of Western-European origin. All participants indicated that there was not one specific reason for rejecting pertussis VdP yet accepting infant vaccination against pertussis. Their decision-making process was complex, influenced by prior experiences and pre-established views, outcome expectations, information service, trust in vaccinations and professionals, decision-making abilities, and organisational determinants. Conclusion: Both decisions to decline the pertussis VdP and to accept infant pertussis vaccination take place within a dynamic societal context. Open conversations between pregnant women and healthcare professionals about VdP and infant vaccinations are essential to support informed decision-making. Understanding this process can help healthcare organisations tailor and personalise vaccination services, moving away from standardised procedures.