Parental intent to accept postnatal RSV monoclonal antibody immunisation for infants in the UK

Abstract Respiratory syncytial virus (RSV) is a leading cause of infant morbidity and hospitalisation in the UK. Postnatal monoclonal antibody (mAb) immunisation can protect infants, but implementation depends on parental acceptance. We surveyed 12,326 UK parents of children under 18 years in August–September 2024, measuring intent to accept a hypothetical RSV mAb injection for an infant if free through the National Health Service. We estimated national and sub-national intent using multilevel regression and poststratification aligned to UK census data, assessed socio-demographic and behavioural determinants, and embedded an online randomised controlled trial in which a control arm received no additional timing or disease-burden information and six intervention arms varied this information. Estimated national RSV mAb intent was high, with 88.8% leaning towards or definitively intending to immunise, although only 54.0% expressed firm intent. Intent was slightly lower in urban areas, especially London, and among older parents, those born outside the UK, and some ethnic minority groups. Belief in vaccine safety, importance, and trust in health workers were strong positive predictors of intent. Information that the mAb would be administered shortly after birth reduced post-exposure intent relative to control, highlighting the importance of timing, framing, and communication for equitable uptake across groups.