• A vaccine from GlaxoSmithKline showed the potential to protect adults ages 50 to 59 from respiratory syncytial virus in a late-stage clinical trial.
• The preliminary trial results suggest that GSK's shot could help protect a wider population from RSV, which causes thousands of hospitalizations and deaths among older Americans each year.
• The shot, known as Arexvy, is approved in the U.S., Europe, Japan and other countries for adults ages 60 and older. 

A vaccine from GlaxoSmithKline showed the potential to protect adults ages 50 to 59 from respiratory syncytial virus in a late-stage clinical trial, the company said Wednesday.

The initial trial results suggest that GSK's shot, known as Arexvy, could help protect a wider population from RSV, a disease that causes thousands of hospitalizations and deaths among older Americans each year. Currently, Arexvy is approved in the U.S., Europe, Japan and other countries for adults ages 60 and older. 

A single dose of the British drugmaker's shot elicited an immune response in adults ages 50 to 59 who are at an increased risk of catching RSV due to certain underlying medical conditions. 

The immune response wasn't worse than that observed in adults 60 and above, GSK said in a release. A previous late-stage trial on that older age group found that the shot was nearly 83% effective at preventing lower respiratory tract disease caused by RSV.

Safety data in adults ages 50 to 59 was also consistent with data in adults 60 and above, according to GSK.

The drugmaker said it plans to present final results from the trial at an upcoming medical conference and submit them for publication in a peer-reviewed journal. GSK added that it is "on track" to become the first company to submit data on this age group to the Food and Drug Administration and other regulators, and expects a decision on a potential label expansion in 2024. 

"We will submit these data for regulatory review as quickly as possible with the goal of offering adults in this age group the option of a vaccine for the first time," Tony Wood, GSK's chief scientific officer, said in a release. 

Pfizer is the only other company with an approved RSV vaccine on the market. The company's shot is approved for adults 60 and older and expectant mothers who can pass on protection to their fetuses.

Pfizer did not immediately respond to a request for comment on whether it will present its own data on adults ages 50 to 59.

U.S. health officials are banking on the shots from Pfizer and GSK to help the country combat this year's RSV season. RSV and other respiratory viruses such as the flu are already starting to circulate, but so far at lower rates than this time last year, the Centers for Disease Control and Prevention said last week. 

The U.S. suffered an unusually severe RSV season last year. Cases of the virus in children and older adults overwhelmed hospitals across the country, largely because the public stopped practicing Covid pandemic health measures that had helped keep the spread of RSV low. 

RSV usually causes mild, cold-like symptoms. But each year the virus kills 6,000 to 10,000 seniors and a few hundred children younger than 5, according to the CDC.

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