Uptake of intra‐muscular vitamin K administration after birth: A national cohort study

Aim A long‐acting monoclonal antibody against RSV (nirsevimab), given as an injection shortly after birth, is currently being rolled out globally. Carer acceptance of intra‐muscular (IM) vitamin K, another injection given shortly after birth, could serve to indicate the acceptability of nirsevimab. Methods We analysed a national dataset of postnatal health visitor visits in Scotland; individual‐level data on gestation were not available. The primary outcome measure was the modality of administration of vitamin K; potential explanatory variables were maternal age, infant ethnicity, English as a first language, and measures of socio‐economic deprivation. We examined associations between IM vitamin K administration or oral/no vitamin K and each explanatory variable. Results From 2019 to 2021, questionnaires were available for 142 857 infants; data was missing for 2.7%. IM Vitamin K uptake was high: 95.5% of carers consented, with 1.1% requesting oral vitamin K and 0.9% refusing vitamin K altogether. Infant ethnicity, use of English as a first language, socio‐economic status and maternal age were not associated with reduced uptake of IM vitamin K. Conclusion If IM Vitamin K administration is a valid proxy measure for nirsevimab acceptance, we did not identify groups that might require increased engagement prior to nirsevimab roll‐out.