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

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.

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.

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.

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.