The US Food and Drug Administration wants to streamline the Covid-19 vaccine process to more closely resemble what happens with the flu shot, according to documents posted online Monday. This may include streamlining vaccine composition, immunization schedules and periodic updates of Covid-19 vaccines.
The FDA said it expects to evaluate circulating coronavirus strains at least once a year and to decide in June which strains will be selected for the fall season, similar to the process of updating the annual flu vaccine.
Going forward, the agency said, most people may only need one dose of the latest Covid-19 shot to restore protection, regardless of how many shots they’ve had before. According to the FDA’s briefing document for vaccine advisors, two doses may be necessary for the very young and unexposed, elderly, or immunocompromised people.
The agency is calling for a shift to a single vaccine formulation rather than the combination of monovalent vaccines currently used for primary shots, which target only one strain, and bivalent vaccines, currently used for booster doses, which target multiple strains.
The FDA briefing documents do not say whether the annual shot contains one strain, two strains or more. The annual flu vaccine immunizes against four strains.
“This simplification of vaccine composition should reduce complexity, reduce vaccine administration errors due to the complexity of the number of different vial presentations, and potentially increase vaccine compliance by allowing for clearer communication,” the FDA said.
The agency’s independent vaccine advisers, the Vaccines and Related Biologics Advisory Committee, are scheduled to meet Thursday to discuss the future of Covid-19 vaccine regimens and will be asked to vote on whether to recommend parts of the FDA’s plan.
Vaccine experts have had mixed responses.
Former member of the FDA’s expert advisory board, Dr. from the Mayo Clinic. Gregory Poland says the first thing he needs to do is show what he expects the annual vaccination to accomplish.
“They will have to decide what the purpose of using existing vaccines is,” said Poland, who studies how the body reacts to vaccines. “If it’s to prevent serious illness and death, we’re already there.”
Before considering switching to annual amplifiers, he would like to see data on how effective the current updated amplifiers are against the latest Omicron subvariants.
“Efficacy data that continues to be tested predates the BQ and XBB subvariants,” Poland said.
The committee should demand full transparency from the FDA and drug manufacturers when weighing its decisions, he said. He was very concerned that the agency had not shared all the information on divalent enhancers with the advisory committee in June.
Dr. Peter Hotez, dean of Baylor College of Medicine’s National School of Tropical Medicine, said he sees the annual update plan as a balance between what science needs to fight the virus and what’s actually practical.
“I think it’s a balance of trying to do what the science says, which needs adaptation and flexibility. However, it is unlikely that companies will be able to make this transition more than once a year,” he said.
But this plan has some weaknesses, he notes. Annual updates are good as the virus continues to gradually evolve based on previously circulating viruses. But he questions whether the world has enough genomic surveillance to catch a radically different variant coming out of left field like Omicron.
“We don’t have control mechanisms on a global scale. Globally, we do not have a genomic sequence. We don’t have the carefully orchestrated dance for surveillance of the coronavirus that took decades to set up for surveillance of the flu,” Hotez said.
Dr. John Wherry, director of the Institute of Immunology at the University of Pennsylvania, studies how the second line of immune defenders, called T-cells, fight off strains of the coronavirus.
The answer is that things are looking pretty good. Although our antibody levels decline in about three months, our T-cells remain for much longer—up to nine months so far—and are thought to be a component of immunity that protects against severe outcomes such as hospitalization. and death.
Although no measurable decline in T-cells has been seen over time, Wherry says he supports the FDA’s annual Covid-19 vaccine plan.
“Recommending vaccines regularly as part of your routine health care is something we need to do,” he said. “The annual boost with the vaccine will really help make your T-cells more adaptive, renew them and keep us in a position to protect us behind the antibodies.”
This means that boosters should offer some benefits in the short and long term.