The first vaccines to guard against the respiratory illness RSV will soon be available for some older adults, ages 60 and over, after the CDC formally backed recommendations for the shots.

The move, announced Thursday, followed a vote at a meeting of the CDC's Advisory Committee on Immunization Practices earlier this month on the new vaccines, and will trigger federal requirements on insurance coverage of vaccinations. The FDA approved the shots, GSK's Arexvy and Pfizer's Abrysvo, earlier this year.

The new guidance stops short of a full-throated recommendation for all eligible older adults to get the shots. Instead, the panel called for "shared clinical decision-making" between doctors and patients to decide whether the individual benefits outweigh the risks.

"This means these individuals may receive a single dose of the vaccine based on discussions with their healthcare provider about whether RSV vaccination is right for them," the CDC said in a statement.

Among seniors, those in their early 60s are less likely to face severe disease from RSV — which stands for respiratory syncytial virus — compared to their oldest peers. A handful of very rare cases of severe "inflammatory neurologic events" were also reported in vaccine trials, narrowing the balance of benefits versus risks.

The potential side effects are so rare that assessing whether they are simply "due to random chance" will not be possible until studies done after the shots are rolled out, scrutinizing large databases of health records from people who received the vaccines.

CDC officials assured the panel that they would closely follow data from their vaccine safety systems on the launch of the two new RSV vaccines. 

"I want to remind everyone that we have one of the best vaccine safety systems in the world. We have the ability to rapidly acquire information, rapidly assess it, and act on it. We saw that during the COVID pandemic, that system is viable, and is in place," the CDC's Dr. José Romero, director of the National Center for Immunization and Respiratory Diseases, told the panel.

Vaccine makers are still studying when seniors might need to come back for a booster dose of RSV vaccine in the coming years. They also have yet to decide on a final price, further complicating broader recommendations.

GSK said their vaccine could be priced between $200 and $295 per dose, higher than they initially told the committee, given new data suggesting the vaccine could offer protection through at least two RSV seasons. Pfizer said their shots could be between $180 to $270.

At higher prices, federal modeling led some on the panel to worry the shots might not be cost-effective as "a reasonable and efficient allocation of resources," especially for the youngest of those approved to get the shots.

A delay to the vote was floated during the meeting, pending the final prices locked in by each drugmaker. 

However, time will be of the essence to roll out shots to those most at risk, some said. RSV vaccines will be most effective at saving lives if given before infections climb, which happened unusually early last year.

"Lives, hospitalizations, we could have a significant impact this year. So that's why we wouldn't want to delay further," said Dr. Camille Kotton, chair of the committee's work group on the issue, during the meeting.

Kotton pointed to further studies that are expected to yield results on RSV in the coming years, as well as additional new vaccines in the pipeline.

Doctors and vaccine makers are generally not required to follow the CDC's recommendations on how to use approved vaccines. However, so-called "off-label" use — such as vaccinating those under 60 years old with the RSV shots — may not be covered by insurance.

The FDA is also expected to decide on new approval of the first options to protect infants from RSV later this year. The ACIP is also preparing to eventually vote on those too.

"This field will undoubtedly change within the next five to 10 years. We'll learn a lot more. So we're trying to make a decision as best we can with the data we have now, at this time," Kotton said.

In:
• RSV
• Vaccine
• Respiratory Syncytial Virus

Alexander Tin

CBS News reporter covering public health and the pandemic.