GSK has secured FDA expansion of its respiratory syncytial virus vaccine Aleksby for adults aged 18 to 49 who are at high risk of lower respiratory tract illness caused by the virus.
The green light puts GSK on a level playing field with Pfizer and Moderna, which have secured support for RSV vaccinations in 2025 and 2024, respectively. All three vaccinations were originally approved for RSV prophylaxis in adults age 60 and older.
In June 2024, GSK received FDA approval for at-risk adults aged 50 and older, and Pfizer achieved an even larger age-at-risk expansion four months later.
The FDA’s nod brings Europe and the United States in line with Europe and the United States, which approved Alexby for use in at-risk adults in the same age group in January.
“This age expansion will help address a critical medical need for U.S. adults who are at increased risk for severe RSV disease due to certain underlying medical conditions and help alleviate pressure on the health care system,” Dr. Sanjay Gurunathan, GSK head of vaccine research and development, said in the release.
About 17,000 people between the ages of 18 and 49 are hospitalized with RSV each year in the United States, and most infected people have chronic health conditions that put them at risk for severe RSV, according to GSK.
As with all vaccine approvals, GSK cannot supply Arexvy to patients ages 18 to 49 until it receives approval from the Centers for Disease Control and Prevention (CDC).
While CDC approvals were once considered routine, recent regulatory decisions have become less predictable. For example, in 2024, the CDC accepted a recommendation from the Advisory Committee on Immunization Practices (ACIP) to scale back its recommendation for RSV vaccination for at-risk adults ages 60 to 74.
GSK’s new approval comes amid stress on the U.S. vaccination landscape In December, the CDC changed the immunization schedule for U.S. children, reducing the previously recommended six doses.
Additionally, vaccination against respiratory syncytial virus, the leading cause of infant hospitalization in the United States, is currently limited to high-risk children and children whose mothers have not been vaccinated, according to the CDC.
In 2023, the first year of Arexvy’s launch, GSK reported global sales of £1.2 billion ($1.49 billion), which then fell to £593 million ($757 million) in 2024 and £590 million ($777 million) last year. Meanwhile, sales of Pfizer’s Abrisvo rose from $755 million in 2024 to $1.03 billion last year.
