FDA proposes switching to annual coronavirus vaccine, mimicking flu model
Americans would receive an annual vaccine to protect against the coronavirus under a once-a-year regimen akin to what is used for influenza shots, according to a new strategy outlined Monday by the Food and Drug Administration.
The agency, in briefing documents released in advance of a meeting this week with its vaccine advisers, said the goal is to determine in the spring which strain will pose the greatest threat the following winter. A vaccine targeting that strain would then be administered in the fall, in the hopes that a streamlined effort would encourage vaccine uptake.
The evidence suggests that "moving forward, most individuals may only need to receive one dose" of a coronavirus vaccine "to restore protective immunity for a period of time," the FDA said in the briefing papers. The change in strategy is expected to be one of the key topics discussed at the agency's vaccine advisory committee meeting scheduled for Thursday. The advisers' views will be taken into consideration when the FDA decides on a final plan.
The FDA's proposal represents a shift from its strategy of pushing boosters to counter variant threats - an effort that ran into resistance from the public, which showed little interest in getting repeated shots. The new blueprint for an annual dose of protection drew conflicting reactions.
Robert M. Wachter, chairman of the department of medicine at the University of California at San Francisco, said the proposed FDA approach "seems reasonable" - a step that could "save a lot of lives" by streamlining the complicated regimen that might have discouraged people from getting the vaccines.
Others said the coronavirus vaccines did not possess sufficient durability to protect people for a year.
Eric Topol, a professor of molecular medicine at Scripps Research, called the idea of an annual shot "a flawed approach," saying no data exists to support the idea that a vaccine provides protection beyond four to six months. Topol said people who have never had COVID-19 could be at particular risk because they would not have a reservoir of naturally generated disease-fighting antibodies to draw from.
The FDA suggested Monday that the annual formulation for coronavirus vaccines would be chosen every June, in time to be manufactured and administered by September as part of a yearly immunization campaign. The goal would be to select the strain most likely to be dominant in the winter, when people are indoors and coronavirus cases typically rise. The strategy suggests a recognition that the virus has become endemic, a part of the American health-care scene that will recur year after year.
If there were an emergency - the appearance of a more dangerous variant capable of evading vaccine-endowed immunity - the FDA would call an impromptu meeting of its vaccine advisers and select a new strain to counter the threat, the agency indicated.
While most people would get an annual shot, people who are older, very young or immunocompromised, or who have serious health problems, might need two doses, the FDA briefing document said.
Over the past three years, the FDA has struggled to deal with the evolving virus. The agency last year authorized an updated bivalent vaccine that targeted the original strain of the virus along with omicron subvariants BA.4 and BA.5. But by the time the booster was released, another variant was ascending rapidly.
In addition, the uptake of the vaccine has been low even among older people who are most vulnerable. Fewer than 40 percent of people 65 and older have received the updated shot, the Centers for Disease Control and Prevention says.
Lawrence O. Gostin, a public health professor at Georgetown Law, said the policy proposed by the FDA would probably work well for younger, healthier people but perhaps not as well for older individuals, who might need more shots.
"I think I would transition only for the young, healthy Americans and continue boosters for the elderly," Gostin said.
The FDA, according to the document, also is seeking an endorsement from the committee to retire the original vaccination formula that entered the market in late 2020 - the monovalent version that targets the original virus. That means the updated, bivalent booster would be used for the original two-shot series as well as for the booster - until a new strain is chosen.
"This simplification of vaccine composition should reduce complexity, decrease vaccine administration errors due to the complexity of the number of different vial presentations, and potentially increase vaccine compliance by allowing clearer communication," the FDA said.
Scientists say they have learned that the vaccines provide the strongest protection against the virus for the first three or four months after injection. For some months after that, the shots remain protective against severe illness, but then protection wanes. The hope is that the lowest level of protection will occur during the summer, when coronavirus surges tend to be less severe.
The fact that many Americans have been infected with the virus should provide additional protection, scientists say.
The FDA has been criticized by some doctors, including members of its vaccine advisory committee, for pushing for broad use of variant-specific boosters to stave off COVID-19. Paul A. Offit, a member of the panel who is a vaccine expert at Children's Hospital of Philadelphia, wrote in the New England Journal of Medicine recently that it is fruitless to try to "prevent all symptomatic infections in healthy, young people by boosting them with vaccines containing mRNA from strains that might disappear a few months later."
Offit said such boosters should be reserved for older people, or those who are immunocompromised or have multiple medical conditions.
Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, said in an interview that he disagreed, adding that he is not sure an annual flu model will work for the coronavirus, in part because mRNA vaccines don't last an entire year and because more needs to be learned about variants.
"There may be too many unknowns," he said.
Jeanne Marrazzo, director of the division of infectious diseases at the University of Alabama at Birmingham School of Medicine, said that the FDA's proposal for an annual coronavirus shot relies on a "good goal" but that it's not clear how to predict the course of a virus that has been so wildly unpredictable.
Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security, criticized the FDA approach, saying the agency was using a "one size fits all" model that needs to be adjusted to reflect that some individuals need to get booster shots more frequently than others. He said the FDA should adopt a risk-based approach based on people's specific risks.
"Precision medicine makes sense," Adalja said. "This needs to be individualized."