The FDA’s goal is to make a recommendation by early July on a strain composition, preferably the corresponding variant for which current vaccines are least effective, so that companies can produce doses in time to start boosters in earnest by October, said Peter Marks, director. Center for Evaluation and Research of Biologicals Agency.
“If we want them to be available by early autumn, it has to happen very soon,” Marks said. The agency usually makes a recommendation based on the vote of an expert group, although not always.
Disagreements and questions to view: However, two members of the panel opposed the recommendation, and Paul Offit of the Children’s Hospital of Philadelphia took issue with the lack of data on the need for updated vaccine formulations when the scientific community had not yet determined the correlate of their protection – the level at which the body’s immune response to antibodies and memory cells provides adequate protection against the virus.
“I’m still not sure we have the information we need to support this new product in a meaningful way,” he said.
Vaccine manufacturers have said that producing booster formulations targeting BA.4 and BA.5 would push their delivery times to a later date than if they had been tasked with producing formulations for a specific BA.1 strain.
Moderna said it could have a subvariant-targeted vaccine ready by the end of October, compared to August for bivalent formulations targeting the original Omicron strain. Pfizer said the updated vaccine would be ready by the first week of October.
Committee members expressed concern about implementation confusion among healthcare providers if a separate booster formula were made available alongside the original vaccine recipes that have been used for both primary and booster vaccinations since December 2020.
What’s next: The FDA must decide whether and how to recommend strain composition for Covid-19 vaccines so that manufacturers can start making updated vaccines.
It is also unclear which populations will be eligible for booster shots in the coming months. Pfizer and Moderna’s data covers adults to date, especially those over 50, and the Biden administration has said it’s running out of money to ensure it can continue to provide Covid vaccines to all Americans for free.