US regulators on Tuesday authorized another COVID-19 booster for those aged 50 and over, a step toward extra protection for the most vulnerable in the event of a resurgence of the coronavirus.
The Food and Drug Administration’s decision to open a fourth dose of Pfizer or Moderna vaccine to these people at least four months after their previous booster shot.
So far, the FDA has cleared the fourth dose only for people 12 years of age and older with severely weakened immune systems. The agency said this particularly fragile group could also receive an extra dose of the booster, a fifth.
The latest expansion, regardless of people’s health, allows millions more Americans to be added – and the question is whether everyone who is eligible should rush out and get it. The Centers for Disease Control and Prevention is expected to step in.
The move comes at a time of great uncertainty. COVID-19 infections have dropped to lows following a winter spike in the super-contagious variant Omicron. CDC data show that two doses of vaccine plus one booster still provide strong protection against morbidity and mortality.
But a sibling of Omicron is causing a worrying increase in infections in Europe – and spread in the US – even if vaccinations have stalled. About two-thirds of Americans are fully vaccinated, and half of those eligible for the first booster have not.
Pfizer asked the FDA to remove the fourth injection for people 65 and older, while Moderna requested another dose for all adults “to give flexibility” for the government to decide who actually needs the shot.
There’s very little evidence to suggest what benefit another booster might offer right now. The FDA made the decision without the participation of an independent panel of experts wrestle with the amount of data required to enlarge the image.
“There may be a reason to reduce the reservoir a little bit” for older people and those who are not involved, said immunologist E. John Wherry of the University of Pennsylvania, who was not involved in the government’s decision. people with other health conditions.
But while he’s encouraged older friends and relatives to follow the advice, 50-year-old Wherry – who is healthy, vaccinated, and fortified – has no immediate plans to get a fourth shot. With protection against serious illness still strong, “I’ll wait until it seems necessary.”
No COVID-19 vaccine is as potent against Omicron gene mutations as they are against earlier versions of the virus. In addition, protection against mild infections fades over time. But the immune system builds many layers of protection and the kind that prevent serious illness and death is holding up.
In the US wave of Omicrons, two doses were nearly 80 percent effective for requiring mechanical ventilation or dying — and a booster dose pushed that level of protection to 94%, the CDC recently reported. The vaccine’s effectiveness was lowest – 74% – in immunocompromised people, most of whom had not received a third dose.
U.S. health officials also looked to Israel, where in the Omicron operation opened a fourth dose to people 60 years of age and older at least four months after the last shot. Preliminary data posted online last week suggests some benefit: Israeli researchers counted 92 deaths out of more than 328,000 people who received the extra injection, compared with 232 deaths out of 234,000. who skipped the fourth dose.
What is not yet clear is how long any additional benefit from another booster will last, and therefore when to get it.
“When is the really difficult part. Ideally, we should calculate the booster dose just before the increase, but we don’t always know when that will happen,” said Dr. William Moss of the Johns Hopkins Bloomberg School of Public Health.
Plus, the longer interval between shots helps the immune system form a stronger, more cross-reactive defense.
“If you have a booster that’s too close together, it doesn’t do any harm – you won’t get much benefit from it,” says Wherry.
The latest booster expansion may not be the last: Next week, the government will hold a public meeting to debate whether people will finally need a fourth dose, possibly in summer. collection, the original vaccine or an up-to-date shot.
As for the vaccine update, human studies – of Omicron-targeted injections alone or in combination with the parent vaccine – are underway. The National Institutes of Health recently tested it on monkeys and found “no significant benefit” from using an enhancer that only targets Omicron.
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