Biopharmaceutical company GSK plc (LSE: GSK) (NYSE: GSK) announced on Monday that it has submitted an application to the US Food and Drug Administration (FDA) to expand the approved use of its respiratory syncytial virus (RSV) vaccine, Arexvy, to include adults aged 18-49 who are at increased risk of severe RSV-related illness. The FDA has accepted the application, with a decision expected in the first half of 2026.

The submission is supported by positive Phase IIIb trial results demonstrating non-inferior immune responses and consistent safety data in at-risk adults aged 18–49 compared with adults over 60. Arexvy is currently approved in the US for use in individuals aged 60 and above, and for those aged 50–59 with risk factors such as chronic obstructive pulmonary disease (COPD), asthma, congestive heart failure and coronary heart disease.

RSV affects approximately 64 million people globally each year. In the US, over 21 million adults under 50 are estimated to have at least one risk factor for severe RSV outcomes, making this an important target group for expanded protection. GSK is also pursuing broader approval in other major markets, including the European Economic Area and Japan.

Arexvy contains the RSVPreF3 antigen combined with GSK's proprietary AS01E adjuvant and has been approved for use in older adults in more than 60 countries. The vaccine aims to prevent lower respiratory tract disease caused by RSV, a virus that can cause serious complications in vulnerable populations.