Will Americans need a 3rd dose of the coronavirus vaccine?

LONDON — Days after Israel announced it would offer a third dose of the Pfizer coronavirus vaccine to people 60 and over, some European countries are following suit.

On Sunday, the British newspaper the Telegraph reported that 32 million Britons would be offered the so-called booster shots as early as next month. Germany announced on Monday that it would similarly give booster shots to vulnerable populations in September. And on Tuesday, Sweden announced its own booster shot program — for next year — for most of its adult population.

Some of these nations have been applauded for their early efforts in rolling out vaccinations, but the rise of the highly contagious Delta variant and concerns over waning vaccine immunity have left countries around the world searching for ways to further protect fully vaccinated vulnerable people.

But what does it mean for vaccinated populations in the U.S.? And will Americans be offered a third dose in the future?

Ariel Quero
A woman receives a dose of a vaccine against the coronavirus at a clinic in Bronx, N.Y. (Reuters)

The Biden administration has indicated that it’s likely that vulnerable adults — those who are 65 and older and those who have compromised immune systems — will be given the opportunity for a booster shot at some point in the future.

But just weeks ago, some U.S. health officials rejected the idea. Both the Centers for Disease Control and Prevention and the Food and Drug Administration said in late July that Americans don’t need third doses quite yet.

The rejection came after a July report by drugmaker Pfizer that said it has seen waning immunity from its coronavirus vaccine. Pfizer announced that it would seek emergency use authorization by the FDA for use of a third dose in August. The study suggested a third dose of its vaccine can strongly boost protection against the Delta variant.

But some scientists are skeptical of the findings of the study.

A demonstrator
A demonstrator at Pfizer headquarters in New York City demands a fairer global distribution of COVID-19 vaccines, March 11, 2021. (Reuters)

“It’s really hard to do the kind of studies that would really give you a full picture of somebody’s immune system,” Dr. Gigi Gronvall, a senior scholar at the Johns Hopkins Center for Health Security, told Yahoo News.

“The Pfizer study that was released was with a very small number of people, and [it was] looking at antibodies, which are the easiest things to measure and somebody’s immune response. But it's not the only part of somebody’s immune response,” Gronvall explained.

A separate study from the Israeli government, released in late July, also suggested a downward trend in the effectiveness over time of the Pfizer vaccine, the only COVID-19 shot available in the country. The report compared data from late June and early July, when the vaccine was 39 percent effective at preventing infection in the region, to data from January to early April, when estimates were much higher, at 95 percent.

However, health officials also warned that those results could have been skewed by a variety of factors, including data size and the short length of time analyzed.

There is currently no scientific consensus on booster shots. Other studies have indicated long-lasting protection from vaccines made by Pfizer and Moderna, shots that use the same mRNA technology, but the exact length of time protection is provided for is still largely unknown.

“All indicators are that for most people, they don’t need that third shot right now,” Gronvall told Yahoo News, “And there there may be a time when that happens, but right now, the effort has to be on getting the people who haven't even had one shot that opportunity to, to get their immune systems on board,” she added.

“I think there are certain subsets of all populations who may benefit from additional immunization,” said Dr. Chris Beyrer, professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.

“The first of those would be people with immune suppression who are immunocompromised … and the elderly who may also be vulnerable, both to severe COVID outcomes and to waning immunity,” Beyrer said.

The Pfizer/BioNTech vaccine
A nurse in Israel prepares a third dose of the Pfizer/BioNTech vaccine. (AFP via Getty Images)

Some scientists are also cautious of studies and data released by Pfizer, pointing out that the pharmaceutical giant could profit from the purchase of more doses.

“You have to take the [Pfizer studies] with a couple of grains of salt and evaluate the data as it is, and as far as real-world data, right now, most people can be confident that their immune systems are ready after two doses,” Gronvall said.

While other health experts and officials have also raised concerns about government’s making the decision to offer third doses when many people still haven’t received a first dose.

“Here we are in a situation where people who’ve already had two doses may be contemplating boosters,” Beyrer told Yahoo News, “When our biggest problem in the United States right now is the substantial proportion of Americans who are not immunized at all. ... That’s the focus we have to really work on.”

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