An expert panel that advises the Centers for Disease Control and Prevention on vaccination policy informally endorsed a plan Wednesday to offer an additional Covid-19 booster shot to people 65 and older as well as people who are immunocompromised, and to simplify the Covid vaccine schedule.
The Advisory Committee on Immunization Practices was not asked to vote on the changes, announced Tuesday by the Food and Drug Administration. But in their discussions, the committee of outside experts appeared broadly supportive of the new guidance.
CDC Director Rochelle Walensky signed off on the changes later Wednesday. The action allows older adults who have gone more than four months since their last vaccine dose and immunocompromised people who have gone two months to get another dose of the bivalent messenger RNA vaccines made by either Moderna or the Pfizer-BioNTech partnership.
Beyond this second dose of bivalent vaccine, people who are immunocompromised will be able to get additional doses going forward, if their health care provider believes they are warranted.
The provision for additional doses does not apply to the other vaccines authorized in the United States, those made by Novavax and Johnson & Johnson. Neither of those vaccines has been broadly used here, and the remaining U.S. supplies of the J&J vaccine are set to expire next month.
Several members of the committee asked about the status of the non-mRNA vaccines, neither of which is available in bivalent form. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, told the committee the regulatory agency is in discussions with the other manufacturers to try to chart a path forward.
Under the revised policy, most Americans who have had one dose of the bivalent vaccine are not currently eligible for an additional bivalent booster — though there was strong indication from both FDA and CDC that another shot will be authorized for the autumn.
Marks said discussion of future doses will take place in June when the FDA holds a meeting to decide whether the strains in the vaccines should be updated for a possible fall vaccination campaign.
While research shows that protection against any infection is short-lived and protection against more serious illness also wanes over time, there was some heartening vaccine effectiveness data presented by CDC, drawn from a network of 25 hospitals in 20 states known as the Investigating Respiratory Viruses in the Acutely Ill, or IVY network.
It showed that adults who have not had a bivalent booster but had between two and four doses of monovalent vaccine retain solid protection against the most severe consequences of Covid infection — needing mechanical ventilation or death — for over a year after their most recent shot.
Marks acknowledged the Covid vaccination schedule remains more complicated than is desirable. These changes, he said, are an interim step, with further moves to simplify the schedule likely to come.
While the advice for adults appears to be fairly clear, the new schedule for children 5 and under remains complex, with the two available vaccines for the youngest children requiring differing numbers of doses and eligibility for bivalent boosters hinging on which brand a child received.
“We’re not done,” CDC vaccine expert Sara Oliver said in reference to the need for future rationalization of the schedule.
There were two areas of concern raised by the committee members, relating to young children who are immunocompromised and pregnant people.
Under the new schedule, children aged 6 months to 5 years who are immunocompromised and who were vaccinated with the Moderna vaccine can get additional booster doses, if a health care provider deems them warranted. But children aged 6 months to 4 years who got the Pfizer vaccine cannot. (The different age cutoffs are due to the fact that the two companies chose different age groups when they conducted clinical trials in young children.)
The FDA’s Marks said that puzzling policy was the result of the fact that there were no data on which to recommend additional Pfizer doses in this cohort of kids.
“Unfortunately this was where we were left with the data we had at hand,” he said, adding that the policy may change if the FDA gets additional data.
ACIP Chair Grace Lee, a professor of pediatrics at Stanford University School of Medicine, said the situation leaves clinicians who care for immunocompromised children in a bind. While additional boosters are allowed for those who got the Moderna vaccine, the booster doses of that brand contain less than half the amount of antigen that its original monovalent vaccines contained — raising questions about how well the children will be protected.
“For that population, we don’t have good choices right now, or data to support that we’re going to be able to optimally protect that population with either Pfizer or Moderna,” Lee said, noting some young children who are immunocompromised are still becoming very ill if they contract Covid.
Marks suggested the FDA will make additional adjustments when it receives more data.