Americans over the age of 50 can get a second COVID-19 booster if it has been at least four months since their last vaccination, an opportunity for additional protection for the most vulnerable should the coronavirus rebound.
The Food and Drug Administration on Tuesday authorized an additional dose of the Pfizer or Moderna vaccine for that age group and for certain younger people with severely weakened immune systems.
The Centers for Disease Control and Prevention later recommended the extra shot as an option, but stopped short of urging those eligible to rush to get it right away. That decision expands the additional booster to millions more Americans.
Dr. Rochelle Walensky, director of the CDC, said it was especially important for older Americans (65 and older) and those in their 50s with chronic health conditions, such as heart disease or diabetes, to consider another injection.
“They are more likely to benefit from receiving an additional booster dose at this time,” Walensky said.
There is evidence that protection may decline particularly in higher-risk groups, and for them another booster “will help save lives,” FDA vaccines chief Dr. Peter Marks said.
Despite all the attention over who should get a fourth dose of the Pfizer and Moderna vaccines, only about half of Americans eligible for a third vaccine have received one, and the government urged them to catch up. Two injections plus a booster still offer strong protection against serious illness and death, even during the winter rush of the super contagious omicron variant.
The switch to additional boosters comes at a time of great uncertainty, with limited evidence to determine how much benefit an additional dose might offer at this time. Cases of COVID-19 have dropped to low levels in the US, but all vaccines are less powerful against newer mutants than older versions of the virus, and health officials are watching carefully. an omicron brother that is causing worrying jumps in infections in other countries.
Pfizer had asked the FDA to approve a fourth injection for people 65 and older, while Moderna requested another dose for all adults “to give flexibility” to the government in deciding who really needs it.
The FDA’s Marks said regulators set the age at 50 because that’s when chronic conditions that increase risks from COVID-19 become more common.
Until now, the FDA had allowed a fourth dose of the vaccine only for those who are immunocompromised 12 years of age and older. Vaccines have a harder time revving up severely weakened immune systems, and Marks said their protection also tends to wane sooner. Tuesday’s decision also allows them another booster: a fifth dose. Only the Pfizer vaccine can be used in children up to 12 years of age; Moderna’s is for adults.
What about people who received Johnson & Johnson’s single-dose injection? They were already eligible for a reinforcement of any kind. Of the 1.3 million who received a second J&J injection, the CDC said they can now choose a third dose, either Moderna or Pfizer. For the more than 4 million who received Moderna or Pfizer as their second injection, the CDC says an additional booster is only necessary if they meet newer criteria: a severely weakened immune system or are age 50 or older.
That’s because a CDC study that tracked which boosters J&J recipients initially chose concluded that a second shot of Moderna or Pfizer was superior to a second dose of J&J.
If the new recommendations sound confusing, outside experts say it makes sense to consider additional protection for the most vulnerable.
“There could be a reason to fill the tanks a little bit” for older people and those with other health conditions, said University of Pennsylvania immunologist E. John Wherry, who was not involved in the government’s decision.
But while he encourages his older friends and family to heed the advice, Wherry, 50, who is healthy, vaccinated and beefed up, isn’t planning on getting a fourth shot right away. With protection against serious diseases still going strong, “I’m going to wait until it looks like there’s a need.”
While protection against milder infections naturally declines over time, the immune system builds multiple layers of defense, and the kind that prevents serious illness and death remains.
During the US omicron wave, two doses were nearly 80% effective against needing a ventilator or death, and a booster boosted that protection to 94%, the CDC recently reported. Vaccine effectiveness was lowest (74%) in immunosuppressed people, the vast majority of whom had not received a third dose.
To assess an additional booster, US officials looked to Israel, which opened a fourth dose to people 60 and older during the omicron surge. The FDA said no new safety concerns emerged in a review of 700,000 administered fourth doses.
Preliminary data published online last week suggested some benefit: Israeli researchers counted 92 deaths among more than 328,000 people who got the extra shot, compared with 232 deaths among 234,000 people who missed their fourth dose.
What isn’t clear is how long any additional buff from another booster would last, and therefore when to get it.
“The ‘when’ is a really difficult part. Ideally we would schedule booster doses just before surges, but we don’t always know when that will be,” said Dr. William Moss, a vaccine expert at the Johns Hopkins Bloomberg School of Public Health.
Also, a longer interval between injections helps the immune system mount a stronger and more cross-reactive defense.
“If you put a booster too close to each other, it doesn’t do any damage, you just won’t get much benefit,” Wherry said.
The latest booster expansion may not be the last: Next week, the government will hold a public meeting to discuss whether everyone eventually needs a fourth dose, possibly in the fall, of the original vaccine or an updated vaccine.
Even if the highest-risk Americans get the booster now, Marks said they may need another dose in the fall if regulators decide to modify the vaccine.
For that effort, studies are underway in people of targeted injections of omicrons alone or in combination with the original vaccine. The National Institutes of Health recently tested monkeys and found “no significant advantage” to using a booster that targets only omicron.
AP writer Mike Stobbe contributed to this report.
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