Covid-19 vaccine boosters may be necessary at some point. Here’s what you need to know

Vaccine makers are preparing for a next possible phase of the Covid-19 vaccine rollout: booster doses.

The  on Thursday that it has seen waning immunity from its coronavirus vaccine — although efficacy in preventing serious illness remains high — but did not detail the evidence. It said a third dose may be needed six to 12 months after full vaccination.
The company said it would publish “more definitive data soon” and in August would seek emergency use authorization from the US Food and Drug Administration for a booster dose.
But just hours after Pfizer made its announcement, the saying people who are fully vaccinated do not need booster shots yet.
While boosters are not necessary now, more information is needed to decide whether people might eventually need booster doses of Covid-19 vaccines, and a rise in so-called breakthrough cases could offer a clue in the future,
Members of the CDC’s Advisory Committee on Immunization Practices discussed when it might be time for the agency to make recommendations for booster doses and committee members mostly agreed that more data around the benefits of boosters is needed.
ACIP members agreed that a rise in “breakthrough” Covid-19 cases, which occur after someone has been fully vaccinated, could be a sign in the future that immunity is waning and booster doses of vaccine may be needed.
“What we are looking for is both a very careful look at breakthrough cases and also whether there is currently an uptick in the elderly — that would be pretty clear because they are currently so well controlled,” said ACIP member Dr. Sarah Long, a professor of pediatrics at Drexel University College of Medicine.
“It would be a mistake to be giving booster doses without both some information about number one: Do they boost? And a little bit of safety data,” Long said. “So that we would have some idea that there would be benefit of the booster before we might incur unknown risk.”
Currently three coronavirus vaccines are authorized for emergency use in the United States — the two-dose Pfizer/BioNTech vaccine for people 12 and older, the two-dose Moderna vaccine and the single-dose Johnson & Johnson vaccines for everyone 18 and older.
Some researchers and health officials said they suspect the immunity against Covid-19 these vaccines elicit in the body might wane over time — possibly after a year or more — and might not protect as well against coronavirus variants that could emerge and evolve.
That might mean a vaccinated person would need a booster dose of vaccine to stay protected against the original coronavirus strain and newly emerging variants — somewhat similar to how a tetanus booster is recommended every 10 years or different flu vaccines are recommended each year.

Will booster doses or new vaccines be needed?

“Many people may be familiar with tetanus-toxoid vaccines that are recommended every 10 years — that’s a booster dose. It’s reminding our immune system so that if we ever got exposed to that toxin, our immune system would remember it and respond very quickly,” Dr. William Moss, professor and executive director of the International Vaccine Access Center at , told CNN in May.
In the case of Covid-19 vaccines it remains unknown for how long immune protection lasts, but vaccine developers and health officials know it may not be forever — and that emerging variants could escape immunity.
“There is a little nuance with Covid-19 vaccines,” Moss said.
While typical booster doses use same vaccine someone previously received to remind the immune system about immunity to a pathogen, any future boosters for the Covid-19 shot could use different vaccines altogether.
Currently, “the need for and timing for COVID-19 booster doses have not been established. No additional doses are recommended at this time,” the
But Americans should prepare to have a Covid-19 vaccine booster shot within a year, US Surgeon General Dr. Vivek Murthy told CNN’s Wolf Blitzer in May, saying “people should be prepared for the fact that we may need a booster within a year.”

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