A panel of outside experts to the U.S. CDC narrowed its recommendation for use of respiratory syncytial virus vaccines in older adults this year and held off on recommending their use for adults under age 60.

The U.S. Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices on Wednesday voted to recommend all adults 75 and older, as well as those who are 60 to 74 and have an increased risk of severe RSV disease due to medical conditions, receive the shots.

Last year, GSK and Pfizer went head-to-head with rival RSV shots for all adults aged 60 and over, who could get the vaccine after consulting with a healthcare provider.

Moderna received approval from the U.S. Food and Drug Administration for its shot, mRESVIA, for the same age group last month.

GSK received FDA approval earlier this month to expand use of its vaccine to adults ages 50 to 59 at increased risk from the illness, but the committee postponed endorsing its use in that age group. The committee's work group said the balance of risk and benefits for the shot in that age group is more uncertain.

Although the CDC generally follows the recommendation of its advisers, the final decision rests with the agency's director.

RSV, which typically causes cold-like symptoms, is a leading cause of pneumonia in toddlers and older adults, causing 177,000 hospitalizations and 14,000 deaths in the United States annually.