A major UK-led clinical trial has revealed that surfactant therapy, commonly used to aid premature infants with breathing difficulties, offers no significant benefit to babies on life support battling severe bronchiolitis. This seasonal viral illness hospitalizes thousands of infants each year and the findings, published today, March 21, 2026, in The Lancet Respiratory Medicine, challenge current approaches to managing the most critical cases.
The Bronchiolitis Endotracheal Surfactant Study (BESS) trial, the largest randomized study of its kind, involved 232 critically ill babies across 15 children’s hospitals in England, Scotland, and Northern Ireland. Researchers investigated whether administering surfactant – a substance that helps maintain the lungs inflated – could reduce the duration of ventilation needed for these severely affected infants. Despite being safe, the treatment did not demonstrate a measurable improvement in recovery time.
Understanding Bronchiolitis and Surfactant Therapy
Bronchiolitis, most frequently caused by respiratory syncytial virus (RSV), inflames the small airways in the lungs. While typically affecting babies under one year old, the illness can be particularly dangerous for premature infants and newborns. Babies with bronchiolitis often experience reduced levels of surfactant, mirroring the condition seen in premature babies whose lungs haven’t fully developed. Because surfactant is routinely used to support breathing in premature infants, the study team hypothesized it might also benefit those hospitalized with bronchiolitis.
Professor Calum Semple OBE, lead researcher from the University of Liverpool and Alder Hey Children’s NHS Foundation Trust, explained, “The treatment was safe, but it didn’t make any difference to how long babies stayed on ventilators. We had hoped that surfactant might speed up recovery for these very sick babies, but the evidence doesn’t support this.”
Significant Impact on Winter Hospital Admissions
Bronchiolitis is a leading cause of infant hospitalization during the winter months in the UK. Approximately 25,000 babies are admitted with the condition annually, with around 1,000 requiring intensive care and ventilator support. Currently, there is no specific antiviral treatment for RSV infection, making supportive care – including oxygen and fluids – the mainstay of management. However, a fresh preventative measure is now available: an RSV vaccine offered to pregnant women in the final months of pregnancy.
The BESS trial, funded by the UKRI Medical Research Council (MRC), the National Institute for Health and Care Research (NIHR), and Chiesi Farmaceutici SpA, Italy, ran for six winter seasons, from 2019 to 2024, to ensure robust data collection and account for seasonal variations in RSV prevalence. The study’s design aimed to provide clear guidance for both families and clinicians.
Professor Semple emphasized the importance of preventative measures, stating, “While we continue to research better ways to care for these sick babies, I urge Mums-to-be to accept the offer of the RSV vaccine during pregnancy, which will protect their newborn babies from severe bronchiolitis.”
Researchers underscore that surfactant therapy remains crucial for premature newborns and advocate for continued investigation into targeted treatments specifically for bronchiolitis. Further research is needed to identify alternative strategies for improving outcomes in these vulnerable infants.
Disclaimer: This article provides informational content about medical research and should not be considered medical advice. Always consult with a qualified healthcare professional for diagnosis and treatment of any medical condition.
What this research highlights is the ongoing need for innovative approaches to managing severe bronchiolitis. The focus now shifts towards exploring alternative therapies and refining preventative strategies, particularly with the availability of the new RSV vaccine. Further studies will be critical to understanding the complex interplay between viral infection, lung function, and the potential for targeted interventions.
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