Largest Clinical Trial to Date Confirms Surfactant Therapy Fails to Shorten Ventilator Time for Infants With Severe Bronchiolitis

Largest-ever study finds surfactant therapy does not reduce ventilator time for infants with severe bronchiolitis, focusing attention back on RSV vaccines.

By: AXL Media

Published: Mar 23, 2026, 5:36 AM EDT

Source: Information for this report was sourced from University of Liverpool

The Final Verdict on a Long-Standing Clinical Hypothesis

The Bronchiolitis Endotracheal Surfactant Study, known as the BESS trial, has provided a conclusive answer to a decade-old question regarding the treatment of viral respiratory distress in infants. For years, clinicians observed that babies suffering from severe bronchiolitis exhibited lung conditions similar to those born prematurely, leading to the off-label use of surfactant to assist breathing. However, the data from this major UK-led investigation indicates that while the substance is safe to administer, it does not accelerate recovery or decrease the time a child must remain on mechanical ventilation during the peak of the illness.

Measuring Recovery Across a Multi-Regional Hospital Network

The scope of the study was unprecedented, spanning six winter seasons and integrating data from fifteen specialized children’s facilities across Scotland, England, and Northern Ireland. By focusing on 232 of the most vulnerable patients, researchers were able to rigorously test whether the introduction of external surfactant could compensate for the natural depletion caused by the respiratory syncytial virus. The results were uniform across the various clinical settings, showing that the biological pathway for viral lung injury differs significantly from the developmental respiratory issues seen in preterm neonates, where surfactant remains a vital tool.

Expert Reflection on Trial Safety and Patient Outcomes

Professor Calum Semple of the University of Liverpool emphasized that although the trial did not yield the hoped-for recovery speed, it succeeded in providing families and doctors with evidence-based clarity. According to Semple, the treatment did not pose a safety risk to the infants involved, but its lack of efficacy means that intensive care resources should be directed toward other supportive measures. This finding is particularly significant for the approximately one thousand babies who require intensive care in the UK each year, as it allows medical teams to move past ineffective interventions toward more targeted research.