As the coronavirus morphs into a stubborn and unpredictable facet of everyday life, scientists and federal health officials are converging on a new strategy for immunizing Americans: a vaccination campaign this fall, perhaps with doses that are finely tuned to combat the version of the virus expected to be in circulation.
The plan would borrow heavily from the playbook for distributing annual flu shots, and may become the template for arming Americans against the coronavirus in the years to come.
But some experts question how well a renewed vaccination push would be received by a pandemic-weary public, whether the doses can be rolled out quickly enough to reach the people who need them most — and whether most Americans need additional shots at all.
On June 28, scientific advisers to the Food and Drug Administration will meet to identify the coronavirus variant most likely to be percolating in the United States as temperatures cool. That should leave manufacturers time to decide whether the vaccines’ composition needs to be revised and to ramp up production, hopefully enough to churn out hundreds of millions of doses by October.
Scientific advisers to the F.D.A. have said they would favor switching to a new version of the vaccines only if there were compelling evidence that the current ones were no longer effective and a modified version proved to be better.
The idea is that eligible Americans would be urged to seek immunization against the coronavirus and the flu at the same time this fall, and in the same places: drugstores, doctors’ offices, walk-in clinics and the like. Some important details — like who would be eligible — will be sorted out next month at meetings of scientific advisers to the F.D.A. and the Centers for Disease Control and Prevention.
The plan would mark a departure from the current sequential authorizations of booster shots for various age groups. But the shortcomings of the annual approach have been apparent to flu researchers for years.
Scientists and federal health officials usually decide on the formulation of the flu vaccine in the spring, six months before the flu season. They guess at which version of the flu virus will arrive in the United States by looking at what is already circulating in the Southern Hemisphere, among other factors.
But in some years, “by the time the vaccine is manufactured, the strains have changed, and then you might not have good matching,” Dr. Ofer Levy, director of the precision vaccines program at Boston Children’s Hospital and an adviser to the F.D.A., said.
Among the candidates for a fall Covid shot is a booster designed for Omicron, the odd new avatar of the coronavirus, and combinations that include it. Moderna’s lead booster candidate contains 25 micrograms each of its original vaccine and one tailored to Omicron, Dr. Paul Burton, the company’s chief medical officer, said.
Pfizer is also testing an Omicron-specific vaccine, but will not make a decision on its fall candidate until June, according to Jerica Pitts, a spokeswoman for the company.
Even if the vaccine match isn’t perfect, the boost to immunity should offer some protection against any new variant in the fall, as the flu vaccine does.
The number of Americans who have opted to get booster doses has dwindled with each newly recommended shot. While 90 percent of American adults have received at least one dose of a Covid vaccine, 76 percent opted for a second dose and just 50 percent for a third.
“Considering additional doses for a smaller and smaller return is creating an impression that we don’t have a very effective vaccination program,” Dr. Matthew Daley, a senior investigator at Kaiser Permanente Colorado who heads the C.D.C.’s vaccine working group, said in an interview.
That concern also was articulated by Dr. Beth Bell, director of the National Center for Emerging and Zoonotic Infectious Diseases, at a meeting of the committee last month. Further, a nationwide campaign for another vaccination might stretch supplies, and exhaust pharmacists, providers and public health staff, some advisers warned.
And the experts worry that a push for extra doses this fall, when the risks of severe illness and death are likely to be low for most Americans, might cut into the collective willingness to be immunized later if a new variant surfaces and the public urgently requires it.
Repeated immunizations may even blunt a vaccine’s effectiveness. For example, people who are vaccinated against the flu in a single year develop stronger immunity than those who are vaccinated two years in a row, noted Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York.
Despite the misgivings, federal officials are gearing up for a fall campaign. Pairing the Covid vaccine with flu every year is the simplest way to convince Americans to line up for the vaccines, Peter Marks, director of the F.D.A.’s Center for Biologics Evaluation and Research, said.
“It saves people time,” Dr. Marks said. “And it may mean that more people get both vaccines, which would be a good thing.”
Agency scientists are actively debating the best composition for a fall vaccine with the World Health Organization, the National Institutes of Health, and the vaccine manufacturers, Dr. Marks said.
The F.D.A. favors offering roughly the same formulations of the Pfizer-BioNTech and Moderna vaccines, in order to avoid befuddling people. Otherwise, “I worry that could actually paralyze a vaccine campaign, when the most important thing is that people get boosted at all,” Dr. Marks said.
If the flu vaccine is any indication, however, many Americans will forgo another Covid shot. The Omicron variant has made it clear that preventing all infections is an unattainable goal, and many consider themselves at only a low risk of severe illness or death.
Still, Dr. Marks noted that influenza campaigns also aim to prevent loss of productivity, not just medical consequences.
Before the Omicron variant’s arrival, administration officials said the Covid vaccines were intended to prevent all symptomatic infections, but they have since backed off that stance.
While the Covid vaccines blunted the spread of earlier variants by up to 70 percent, “that’s clearly not true with Omicron,” he said. “It would be nice to have something that did a better job.”
Some experts said that instead of another round of injections, the best candidate for limiting infections would have been a nasal spray that would coat the nose and throat with antibodies to block the virus right at its entryway. But those sprays will not be available in the United States for two or three years at least.
Until Omicron came around, the F.D.A.’s scientists were so excited about mRNA vaccines that they didn’t consider alternative boosters, Dr. Marks added: “We may have been temporarily blinded by the light.”
Still, minimizing the number of infections whenever possible is “obviously a very, very important secondary goal,” Dr. Sara Oliver, who represents the C.D.C. on the Covid-19 vaccine working group, said.
Apart from curtailing the spread of the virus and societal disruption, reduced infections should reduce cases of long Covid, the constellation of symptoms that can persist for months, she said.
The new plan may revive some longstanding tensions. Disagreements about who should recommend vaccines, and for whom, have roiled these agencies for months.
Generally, the F.D.A.’s scientific advisers review the safety and effectiveness of vaccines, and recommend authorization or approval. Experts who advise the C.D.C. then issue guidelines on who should get the vaccines and when.
During the pandemic, the lines between the White House, the F.D.A. and the C.D.C. have often been blurred. “Right now, one of the challenges is that we have a lot of voices who are speaking immunization policy, and historically we’ve just had one voice,” Dr. Daley said.
When the F.D.A. authorized a second booster, for example, it did so only for adults 50 and older — a distinction that would normally have come from the C.D.C.’s vaccine advisers.
The C.D.C. also made a subtle distinction that was lost on many Americans: It recommended that adults older than 50 may get a booster if they wished to, not that they should do so. But the White House’s new Covid czar, Dr. Ashish Jha, endorsed the second booster shots.
“It’s not entirely clear that the White House is in the position of making vaccine recommendations per se, but nonetheless, he said that he recommended it,” Dr. Camille Kotton, an infectious disease physician at Massachusetts General Hospital and a scientific adviser to the C.D.C., said of Dr. Jha.
It’s unclear who would pay for a fall vaccination campaign. The stalemate in Congress over Covid-19 funding jeopardizes the government’s ability to purchase and provide the vaccines to the people who are most in need.
“Without urgent additional funding, we are unable to secure enough booster shots for every American who wants one if they are needed in the fall, and we are unable to secure newer, more effective vaccines that protect against new variants,” Sarah Lovenheim, assistant secretary for public affairs at the Department of Health and Human Services, said.