Danish records show infant hospital admissions for respiratory syncytial virus falling after maternal vaccination

12 November 2026

A study of Danish health records, published in Lancet Regional Health Europe, found that hospital admissions of infants for respiratory syncytial virus fell sharply after Denmark began vaccinating pregnant people nationwide. Antibodies raised by the maternal vaccine cross the placenta and protect babies for roughly their first six months. Take-up of maternal vaccination among eligible people in Denmark was 72 per cent. High-risk newborns whose mothers were not vaccinated, including premature infants, were given nirsevimab, a monoclonal antibody approved in Europe in 2022. Respiratory syncytial virus usually causes mild illness but can be severe or fatal in infants and older adults; the World Health Organization counts about 3.6 million hospitalisations and 100,000 deaths of children under five each year, 97 per cent of those deaths in low- and middle-income countries. Dozens of countries across Europe, Asia and the Americas have since launched immunisation programmes.