One Jab, 72% Fewer Sick Babies

In a new UK study, babies whose mothers received the RSV vaccine while pregnant were significantly less likely to be hospitalized — a striking 72% reduction in severe cases. By transferring protective antibodies through the placenta, vaccinated mothers are giving their babies immunity that lasts through the riskiest early months of life, the journal Lancet Child & Adolescent Health reported.

Getting vaccinated during pregnancy may significantly lower the risk of serious lung infections in newborns, according to new research.

Scientists found that the respiratory syncytial virus (RSV) vaccine, rolled out across the UK in late summer 2024, was linked to a 72% decrease in hospitalizations among babies whose mothers received the shot during pregnancy.

This is the first study to confirm how well the RSV vaccine works for pregnant women in real-world conditions in the UK.

Health experts say increasing vaccination rates among expectant mothers could help reduce the number of infants falling seriously ill each winter, easing the burden on hospitals.

RSV is a widespread virus known for causing cold-like symptoms, but in babies it can lead to bronchiolitis, a serious lung infection. In some cases, infants may need to be admitted to intensive care. RSV is the leading cause of virus-related hospitalizations among babies in the UK and worldwide.

When a pregnant woman receives the RSV vaccine, her body produces antibodies (proteins that fight off infection) in response. These antibodies are passed to the baby through the placenta, offering protection against severe RSV during the first six months of life.

The research team, led by the Universities of Edinburgh and Leicester, recruited 537 babies across England and Scotland who had been admitted to hospital with severe respiratory disease in the winter of 2024-2025, the first season of vaccine implementation. 391 of the babies tested positive for RSV.

Mothers of babies who did not have RSV were two times more likely to have received the vaccine before delivery than the mothers of RSV-positive babies – 41% compared with 19%.

Receiving the vaccine more than 14 days before delivery offered a higher protective effect, with a 72% reduction in hospital admissions compared with 58% for infants whose mothers were vaccinated at any time before delivery.

Experts recommend getting vaccinated as soon as possible from 28 weeks of pregnancy to provide the best protection, as this allows more time for the mother to generate and pass on protective antibodies to the baby, but the jab can be given up to birth.

Previous research has found that only half of expectant mothers in England and Scotland are currently receiving the RSV vaccine, despite its high success at preventing serious illness.

The findings highlight the importance of raising awareness of the availability and effectiveness of the new vaccine to help protect babies, experts say.

The study was published on July 18 in the journal The Lancet Child and Adolescent Health. The research collaboration also included the Universities of Bristol, Oxford, Queen’s University Belfast, UCL, and Imperial College London, and 30 hospitals across England and Scotland.

The study was funded by the Innovative Medicines Initiative (IMI) Respiratory Syncytial Virus Consortium in Europe (RESCEU), the Wellcome Trust, and National Institute for Health and Care Research (NIHR) Health Protection Research Unit in Respiratory Infections, Imperial College London.

Dr. Thomas Williams, study lead from the University of Edinburgh’s Institute for Regeneration and Repair, and Paediatric Consultant at the Royal Hospital for Children and Young People in Edinburgh, said: “With the availability of an effective RSV vaccine shown to significantly reduce the risk of hospitalisation in young infants in the UK, there is an excellent opportunity for pregnant women to get vaccinated and protect themselves and their infants from RSV bronchiolitis this coming winter.”

Professor Damian Roland from the Leicester Hospitals and University and Consultant in Paediatric Emergency Medicine, said: “Our work highlights the value of vaccination and in keeping with the treatment to prevention principle of the NHS 10 Year plan, we would ask all health care systems to consider how they will optimize the roll out of RSV vaccination for mothers.”

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