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The CDC's advisors on Wednesday recommended the newly approved respiratory syncytial virus (RSV) vaccines for older adults, but opted not to give their strongest endorsement.

In a series of two votes, the Advisory Committee on Immunization Practices (ACIP) said that adults 60 and older may receive one dose of the recently approved RSV prefusion F protein-based vaccines after discussions with their health provider.

Originally, the CDC had asked ACIP to vote on broadly recommending the vaccines to people 65 and older, but that plan got tweaked during discussions earlier in the day.

"I'm torn about making a universal recommendation for 65 years of age and older," said Pablo Sanchez, MD, of Nationwide Children's Hospital in Columbus, Ohio, who recommended including the shared decision-making language.

Ultimately, the committee voted on recommendations that included that language both for people 60 to 64 years (13-0 vote in favor, with one abstention) and for people 65 and up (9-5 vote in favor).

Other ACIP members, however, wanted the broad recommendation for all of these older adults.

"I think we should remove the clinical decision-making altogether, and just bring the age down to 60," said Lynn Bahta, RN, MPH, of the Minnesota Department of Health in Saint Paul, suggesting the narrow recommendation might further disparities.

Historically, when the flu vaccine recommendation went from a risk-based recommendation to being recommended for everyone, coverage increased from 38% to 50%.

According to , an estimated 60,000 to 160,000 older adults in the U.S. are hospitalized each year due to RSV infections, and 6,000 to 10,000 deaths are associated with the highly contagious virus in this group.

Throughout the meeting, the ACIP members expressed concerns over the trial data on the RSV vaccines and whether the participants enrolled represented those most at risk for serious outcomes.

"The populations that are at highest risk for severe disease were not included in the trials, and I think that the COVID-19 experience showed us that it is possible to do clinical trials that include people who have comorbidities," said Beth Bell, MD, MPH, of the University of Washington in Seattle.

Approvals of the two vaccines were based on efficacy data spanning a single RSV season. During the meeting on Wednesday, manufacturers presented data showing that vaccine efficacy largely held up through the first part of the second RSV season, but did drop slightly.

Data on GSK's adjuvanted RSV prefusion F protein-based vaccine (Arexvy) showed efficacy against lower-respiratory tract disease (LRTD) dropping from 83% in season one to 77% by the middle of season two, with protection against severe cases dropping from 94% to 85%, respectively.

For Pfizer's unadjuvanted bivalent RSV prefusion F protein vaccine (Abrysvo), protection against LRTD infections with three or more symptoms dropped from 89% in season one to 79% by the middle of season two, with protection against LRTD infections with two or more symptoms dipping from 65% to 49%.

Potential costs of the vaccine was another issue for ACIP, with developers Pfizer and GSK floating prices ranging from $180 to $295 for the new vaccines.

CDC's cost-effectiveness model based on one of the vaccines across two RSV seasons showed that for every 1 million vaccines given, 23,000 outpatient visits, 2,300 hospitalizations, and 120 deaths would be prevented among people 65 and over. For those ages 60 to 64 years, 18,000, 890, and 35, respectively, would be prevented per 1 million doses.

Other concerns stemmed from hints of lower efficacy when the RSV vaccines were given concurrently with the flu shot, with some members suggesting the shots could not be given at the same time.

The CDC noted that despite a signal for increased risk of Guillain-Barre Syndrome or other neurologic inflammatory events in the trials, the risks of these adverse events were not known, and that the agency would rely on ongoing post-marketing surveillance by manufacturers to continue monitoring these safety concerns.

Recommendations of the ACIP are not considered final until they are published in the Morbidity and Mortality Weekly Report.

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