Uptake of intramuscular vitamin K administration after birth and maternal and infant demographic variables: a national cohort study

A long-acting monoclonal antibody against Respiratory Syncytial Virus (RSV), given as a one-off injection shortly after birth, is likely to be introduced soon. We hypothesised that carer acceptance of intra-muscular (IM) vitamin K, another injection given shortly after birth, might serve as a proxy indicator of likely acceptance of any such anti-RSV intervention, given previous associations described between IM vitamin K acceptance and subsequent non-immunisation. Using a national dataset of all postnatal health visitor visits in Scotland from 2018-2021 we explored demographic variables associated with non-acceptance of IM vitamin after birth. We found that in the time period 2019-2021 over 95.5% of carers were documented as consenting to this intervention, with only 1.1% requesting oral vitamin K and 0.9% refusing vitamin K altogether. Infant ethnicity, use of English as a first language at home, socio-economic position and maternal age were not associated with reduced uptake of IM vitamin K. We therefore did not identify any groups that might require increased engagement prior to the roll-out of a long-acting monoclonal antibody for RSV.