WASHINGTON (AP) — With many Americans who got Pfizer vaccinations already rolling up their sleeves for a booster shot, millions of others who received the Moderna or Johnson & Johnson vaccine wait anxiously to learn when it's their turn.
Federal regulators begin tackling that question this week.
On Thursday and Friday, the Food and Drug Administration convenes its independent advisers for the first stage in the process of deciding whether extra doses of the two vaccines should be dispensed and, if so, who should get them and when. The final go-ahead is not expected for at least another week.
Keep scrolling for a breakdown of who's eligible for the Pfizer booster
After the FDA advisers give their recommendation, the agency itself will make an official decision on whether to authorize boosters. Then next week, a panel convened by the Centers for Disease Control and Prevention will offer more specifics on who should get them. Its decision is subject to approval by the CDC director.
The process is meant to bolster public confidence in the vaccines' safety and effectiveness. But it has already led to conflicts and disagreements among various experts and agencies.
For example, last month the CDC advisory panel backed Pfizer boosters at the six-month point for older Americans, nursing home residents and people with underlying health problems. But CDC Director Dr. Rochelle Walensky overruled her advisers and decided boosters should also be offered to those with high-risk jobs such as teachers and health care workers, adding tens of millions more Americans to the list.
Some health experts fear the back-and-forth deliberations are muddling the public effort to persuade the unvaccinated to get their first shots. They worry that the talk of boosters will lead people to wrongly doubt the effectiveness of the vaccines in the first place.
As the FDA's panel meets to review the Moderna and J&J vaccines, its decisions this time are likely to be even more complicated, with experts discussing whether a third Moderna shot should contain just half the original dose and what's the best timing for a second shot of the single-dose J&J vaccine.
The panel will also look into the safety and effectiveness of mixing-and-matching different brands of vaccine, something regulators have not endorsed so far.
An estimated 103 million Americans are fully vaccinated with Pfizer's formula, 69 million with Moderna's and 15 million with J&J's, according to the CDC.
The two initial Moderna shots contain 100 micrograms of vaccine each. But the drugmaker says 50 micrograms ought to be enough for a booster for healthy people.
A company study of 344 people gave them a 50-microgram shot six months after their second dose, and levels of virus-fighting antibodies jumped. Moderna said the booster even triggered a 42-fold rise in antibodies able to target the extra-contagious delta variant.
Side effects were similar to the fevers and aches that Moderna recipients commonly experience after their second regular shot, the company said.
As for people who got the J&J vaccine, the company submitted data to the FDA for different options: a booster shot at two months or at six months. The company did not signal its preference.
J&J released data in September showing that a booster given at two months provided 94% protection against moderate-to-severe COVID-19 infection. The company has not yet disclosed patient data on a six-month booster, but early measures of virus-fighting antibodies suggest it provides even higher protection.
Even without a booster, J&J says, its vaccine remains about 80% effective at preventing COVID-19 hospitalizations in the U.S.
Scientists emphasize that all three vaccines used in the U.S. still offer strong protection against severe disease and death from COVID-19. The issue is how quickly, and how much, protection against milder infection may wane.
In one recent study, researchers compared about 14,000 people who had gotten their first Moderna dose a year ago with 11,000 vaccinated eight months ago. As the delta variant surged in July and August, the more recently vaccinated group had a 36% lower rate of "breakthrough" infections compared with those vaccinated longer ago.
Still, medical experts continue to debate the science and rationale for giving extra shots to those who already have significant protection.
The White House and its top medical advisers announced sweeping plans in August to offer boosters to nearly all adults, citing signs of waning protection and the then-surging delta variant. But they were rebuffed by many experts who said there is little data showing whether such broad use would stop breakthrough infections or curb the overall trajectory of cases.
While the FDA and CDC ultimately scaled back use of Pfizer boosters, Biden administration officials, including Dr. Anthony Fauci, have suggested that extra shots will eventually be recommended for most Americans.
They point to data from Israel showing lower rates of infections and severe disease among people who received a third Pfizer shot.
The FDA meetings come as U.S. vaccinations have climbed back above 1 million per day on average, an increase of more than 50% over the past two weeks. The rise has been driven mainly by Pfizer boosters and employer vaccine mandates.
Here's who is eligible for Pfizer booster shots in the US. An explainer.
Who should get the Pfizer booster?
Who else can consider getting it?
What are the side effects?
Weren't some people already eligible for a third dose?
What if I got J&J?
Where can I get my booster?
Are boosters free?
Am I 'fully vaccinated' without a booster?
Why were boosters so hotly debated?
Are other countries offering boosters?
US booster shots start, even as millions remain unprotected
The U.S. launched a campaign to offer boosters of Pfizer's COVID-19 vaccine to millions of Americans on Friday even as federal health officials stressed the real problem remains getting first shots to the unvaccinated.
“We will not boost our way out of this pandemic,” warned Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention — even though she took the rare step of overruling the advice of her own expert panel to make more people eligible for the booster.
The vast majority of COVID-19 cases and hospitalizations are among the unvaccinated, Walensky noted. And all three COVID-19 vaccines in the U.S. offer strong protection against severe illness, hospitalization and death despite the extra-contagious delta variant that caused cases to soar. But immunity against milder infection appears to wane months after initial vaccination.
People anxious for another Pfizer dose lost no time rolling up their sleeves after Walensky ruled late Thursday on who's eligible: Americans 65 and older and others vulnerable because of underlying health problems or where they work and live — once they're six months past their last dose.
Jen Peck, 52, of Eau Claire, Wisconsin, qualified because of her job as an education math and science consultant. She was vaccinated back in March but worries about unknowingly picking up and spreading an infection. She travels between rural schools where many students and teachers don't wear masks and the younger children can't yet be vaccinated.
“I don’t want to be COVID Mary carrying it around to buildings full of unvaccinated kiddos. I could not live with myself if I carried it from one building to another. That haunts me, the thought of that,” said Peck, who got the extra shot first thing Friday morning.
Health officials must clear up confusion over who should get a booster, and why. For now, the booster campaign is what Walensky called “a first step.” It only applies to people originally vaccinated with shots made by Pfizer and its partner BioNTech. Decisions on boosters for Americans who received Moderna or Johnson & Johnson vaccines are still to come.
President Joe Biden said if you're vaccinated, “You’re in good shape and we’re doing everything we can to keep it that way, which is where the booster comes in.” He urged those now eligible for an extra shot to “go get the booster," saying he'd get his own soon — and that everyone should be patient and wait their turn.
Exactly who should get a booster was a contentious decision as CDC advisers spent two days poring over the evidence. Walensky endorsed most of their choices: People 65 and older, nursing home residents and those ages 50 to 64 who have chronic health problems such as diabetes should be offered one once they're six months past their last Pfizer dose. Those 18 and older with health problems can decide for themselves if they want a booster.
But in an extremely unusual move, Walensky overruled her advisers' objections and decided an additional broad swath of the population also qualifies: People at increased risk of infection — not serious illness — because of their jobs or their living conditions. That includes health care workers, teachers and people in jails or homeless shelters.
“This was scientific close call,” Walensky said Friday. “In that situation it was my call to make.”
Experts say it was only the second time since 2000 that a CDC director overruled its advisory panel.
Health care workers can't come to work if they have even a mild infection and hospitals worried about staffing shortages welcomed that decision.
But some of the CDC's advisers worry that offering boosters so broadly could backfire without better evidence that it really will make a difference beyond the most medically vulnerable.
“My hope is that all of this confusion – or what may feel like confusion – doesn’t send a message to the public that there is any problem with the vaccine,” said Dr. Beth Bell, a University of Washington expert. "I want to make sure people understand these are fantastic vaccines and they work extremely well.”
Dr. Anthony Fauci, the U.S. government’s top infectious disease specialist, cautioned against seeking a Pfizer booster before the recommended six-month mark.
“You get much more of a bang out of the shot” by letting the immune system mature that long so it’s prepared to rev up production of virus-fighting antibodies, he explained.
The U.S. had already authorized third doses of the Pfizer and Moderna vaccines for certain people with weakened immune systems, such as cancer patients and transplant recipients. Other Americans, healthy or not, have managed to get boosters, in some cases simply by asking.
About 182 million Americans are fully vaccinated, or just 55% of the total population. Three-quarters of those 12 and older — the ages eligible for vaccination — have had a first dose.
Associated Press writers Jonathan Lemire in New York, Zeke Miller in Washington and Todd Richmond in Madison, Wisconsin contributed reporting.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
What if I got Moderna? Can I get a Pfizer booster?
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.