NEJM: Latest Research & Medical Advances

February 15, 2026 Dr. Michael Lee – Health Editor Health

A single dose of an experimental respiratory syncytial virus (RSV) vaccine demonstrated 82.6% efficacy against lower respiratory tract disease in adults 60 years and older, according to data published today in the New England Journal of Medicine. The vaccine, developed by GSK, too showed 94.1% efficacy against severe RSV-related lower respiratory tract disease.

The phase 3 trial, conducted internationally and involving nearly 25,000 participants, randomly assigned adults to receive either the RSVPreF3 OA vaccine or a placebo prior to the RSV season. Researchers confirmed vaccine efficacy through reverse-transcriptase polymerase chain reaction (RT-PCR) testing. The study revealed 7 cases of RT-PCR-confirmed RSV-related lower respiratory tract disease in the vaccine group, compared to 40 cases in the placebo group, over a median follow-up period of 6.7 months.

RSV is a common cause of acute respiratory infection, particularly dangerous for older adults, often leading to clinical complications and even death. Currently, no licensed vaccine exists to prevent RSV infection. The GSK vaccine utilizes a prefusion F protein-based candidate, adjuvanted with AS01E, to stimulate an immune response.

The trial also assessed efficacy against RSV-related acute respiratory infection, finding a 71.7% reduction in cases among vaccinated participants. Analyses performed indicated consistent efficacy regardless of RSV subtype (A or B) and the presence of pre-existing conditions. The study authors reported no evident safety concerns associated with the vaccine.

“Our ambition is to protect the many older adults at risk from RSV disease, including those with underlying health conditions, who account for the majority of severe RSV outcomes,” said Tony Wood, Chief Scientific Officer at GSK, in a press statement released by the company. GSK anticipates the vaccine will be available pending regulatory decisions in the United States, European Union, and other countries.

The publication in the New England Journal of Medicine marks the first peer-reviewed release of phase III data for an RSV older adult vaccine candidate. An accompanying expert perspective article in the journal recognizes the significant advancements made in RSV vaccine design, according to GSK.