UK researchers have reported that surfactant therapy, a treatment routinely used to help premature babies breathe, did not shorten ventilator time for infants on life support with severe bronchiolitis. The findings come from the Bronchiolitis Endotracheal Surfactant Study, or BESS, described as the largest-ever randomized study of surfactant for bronchiolitis and funded by the UKRI Medical Research Council, the National Institute for Health and Care Research, and Chiesi Farmaceutici SpA.
The results were published on 21 March 2026 in The Lancet Respiratory Medicine. According to the report, bronchiolitis is most commonly caused by respiratory syncytial virus, or RSV, and can be especially severe in premature and newborn infants. Researchers noted that babies with bronchiolitis have reduced levels of surfactant in their lungs, which helped drive interest in testing whether the therapy might improve outcomes in this setting. Source article
Trial across 15 hospitals found no ventilator-time benefit
The study was carried out across 15 children’s hospitals in England, Scotland and Northern Ireland and included 232 critically ill babies. The central question was whether surfactant could reduce the amount of time these infants needed ventilator support. The answer, based on the trial results, was no.
Professor Calum Semple OBE, the study’s lead from the University of Liverpool and Alder Hey Children’s NHS Foundation Trust, said the treatment was safe but did not make any difference to how long babies stayed on ventilators. He added that the team had hoped surfactant might speed recovery, but the evidence did not support that expectation.
Why the result matters for NHS winter pressures
Bronchiolitis is described as the leading reason babies are admitted to hospital in the UK during winter. It typically affects infants under one year old, and the most severe cases can require intensive care and mechanical ventilation. The trial report states that while most of the roughly 25,000 babies admitted each year recover with oxygen and fluids, around 1,000 of the sickest need ventilator support.
For clinicians, the findings add clarity to an important question in paediatric intensive care: a therapy that works well in premature infants does not appear to offer the same benefit for critically ill babies with bronchiolitis. That distinction may help guide future treatment decisions and research priorities as hospitals continue to manage seasonal respiratory surges.
The BESS trial adds to the evidence base around severe bronchiolitis and RSV-related illness, highlighting the value of large multicentre studies in testing whether established therapies can be repurposed for new patient groups. In this case, the result suggests that surfactant should not be expected to reduce ventilator dependence in infants with the most severe form of the disease.
As winter respiratory admissions remain a pressure point for UK paediatric services, the latest findings underscore the importance of continued research into treatments that can genuinely improve outcomes for vulnerable babies.
Related source: News-Medical report
