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RSV: Winter virus injection could cut baby hospitalisations by 80%

Published: 05 January 2024

A new antibody treatment to protect babies against a common winter virus could reduce hospitalisations by more than 80%, according to an international trial.

The HARMONIE trial is a collaboration between global pharmaceutical company Sanofi, its partner AstraZeneca and the NIHR. It involved 8,058 babies aged under 12 months from the UK, France and Germany. The babies were either in or approaching their first Respiratory Syncytial Virus (RSV) season.

What is RSV?

RSV is the leading cause of hospitalisation in infants. It places a considerable burden on NHS resources, in both primary and secondary care. More than 30,000 under-fives are hospitalised with RSV in the UK every year. It causes between 20 and 30 infant deaths. 

RSV often causes only mild illnesses, such as a cold. However for some babies it leads to more severe lung problems such as bronchiolitis and pneumonia. Most children will have caught it by the time they are two years old. 

The UK’s RSV season typically starts in October, peaks in December and declines by March. 

Trial findings 

The HARMONIE trial showed that a single dose of the antibody nirsevimab offers immediate protection against RSV. It delivered an 83% reduction in RSV infant hospitalisations compared to infants who received no RSV intervention. 

These results suggest the antibody jab could help ease winter pressures on the NHS. Findings have been published in the New England Journal of Medicine.

The new treatment is approved in the UK and is being considered for a national RSV immunisation programme. Data from the trial has already been used to roll out the jab in the US and Spain this winter.

The HARMONIE study is co-led by experts at University Hospital Southampton (UHS), University of Southampton, St George’s University Hospital and University of Nottingham Health Service. It is supported by the NIHR Southampton Clinical Research Facility (CRF) and NIHR Southampton Biomedical Research Centre.

The NIHR helped recruit half the babies in the study through its national Clinical Research Network (CRN). More than 4,000 babies took part in 107 sites across the UK. 

Professor Saul Faust, co-study leader and Director of NIHR Southampton CRF, said: “These latest results show that this long-acting antibody is safe and could protect thousands of babies from hospitalisation when used in conditions similar to routine clinical practice. It is really important information for the UK to help decide on options for the future national RSV immunisation programme.”

Dr Simon Royal, co-study leader, is a General Practitioner, NIHR National Specialty Lead for Primary Care and Honorary Assistant Professor at the University of Nottingham Medical School. He said: “This study has shown how primary care clinicians, hospital specialists and the whole UK NIHR system can work together in a new partnership with industry to deliver rapid data to support a critical NHS need.” 

Dr Matthew Hallsworth, NIHR Director of Strategic Industry Relationships, said: “HARMONIE is a fantastic example of industry and NIHR collaboration. NIHR was instrumental in delivering this study in both secondary and primary care across the county, with the first global participant recruited in a GP site in Nottingham. In addition, this study was the first commercial study that involved an NIHR Associate Principal Investigator, a scheme which encourages in-work training, building on practical experience for healthcare professionals starting their research career.”

The HARMONIE study is funded by Sanofi and AstraZeneca.

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