The Biden administration on Wednesday said Covid-19 booster shots will be necessary "to maximize vaccine-induced protection and prolong its durability," and that Americans who received an mRNA vaccine should get a booster shot eight months after their second shot beginning the week of Sept. 20.

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Details on the health officials' announcement

In a joint statement, senior health officials at HHS said data from the United States and around the world "make[s] it very clear that protection against SARS-Cov-2 infection begins to decrease over time following the initial doses of vaccination," adding that the spread of the delta variant is leading to "reduced protection against mild and moderate disease."

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As a result, the officials said they believe "a booster shot will be needed to maximize vaccine-induced protection and prolong its durability."

Beginning the week of Sept. 20, the Biden administration intends to offer booster shots to Americans eight months after they've had their second dose, according to the statement. The first people to receive booster shots will be those "who were fully vaccinated earliest in the vaccination rollout," including health care providers and nursing home residents.

That timeline applies only to individuals who received either Pfizer-BioNTech's or Moderna's mRNA-based Covid-19 vaccines, the officials said.

The statement also noted the booster shot plan is "subject to FDA conducting an independent evaluation and determination of the safety and effectiveness of a third dose of the Pfizer [or] Moderna mRNA vaccines and CDC's Advisory Committee on Immunization Practices issuing booster dose recommendations based on a thorough review of the evidence."

For those who received Johnson & Johnson's (J&J) vaccine, the officials also anticipate booster shots will be necessary. "Administration of the J&J vaccine did not begin in the U.S. until March 2021, and we expect more data on J&J in the next few weeks," the statement noted. "With [that] data in hand, we will keep the public informed with a timely plan for J&J booster shots as well."

Reaction

Public health experts were divided in their response to the booster plan.

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Matthew Harris, medical director of the coronavirus vaccination program at Northwell Health, said, "What keeps me up at night is the inevitability of a variant that is not responsive to the vaccine, so if this is how we stay ahead of it, I fully support it."

However, other experts expressed concerns about the global health consequences of prioritizing booster shots for Americans. "It's really inequitable and it's not in our interest because you're leaving much of the world unprotected, where you're going to have the emergence of other variants," Céline Gounder, an infectious disease specialist who served on the Biden transition team's Covid-19 advisory board, said.

Earlier this month, World Health Organization Director-General Tedros Adhanom Ghebreyesus said wealthier countries have administered around 100 vaccine doses for every 100 people on average, compared to around 1.5 doses per 100 people in poorer countries.

"We cannot, and we should not, accept countries that have already used most of the global supply of vaccines using even more of it, while the world's most vulnerable people remain unprotected," Tedros said.

But White House press secretary Jen Psaki on Tuesday said it was a "false choice" that the United States couldn't donate vaccines worldwide while also providing booster shots at home.

"The U.S. is far and away the biggest contributor to the global supply," Psaki said. "We will continue to be the arsenal for vaccines around the world. We also have enough supply and have long planned for enough supply should a booster be needed for the eligible population."

What data reveals about the need for vaccine booster shots

The Biden administration's announcement was prompted by data suggesting that immunity provided by Covid-19 vaccines wanes over time, including data from Israel.

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"[I]n the Israeli data the people who got immunized in January are the ones that are now having more breakthrough cases," NIH Director Francis Collins said. "Mostly of course these are symptomatic but not serious, but you're starting to see a little bit of a trend towards some of those requiring hospitalization."

Collins added that the United States is seeing a similar trend, "although right now it still looks as though our vaccine protection is working really well. But we don't want to wait until it's like, 'Oh too late.''"

Separately, a study released last week by the Mayo Clinic found the effectiveness of the Pfizer-BioNTech vaccine against mild Covid-19 infections had dropped, though the vaccine was still effective at preventing hospitalizations.

In addition, data gathered by the New York Times found that breakthrough infections have accounted for at least one in five new Covid-19 cases in California, Colorado, Massachusetts, Oregon, Utah, and Vermont. However, the data shows vaccinated people are still significantly less likely to develop severe Covid-19 or die from the disease than unvaccinated people.

But Sadiya Khan, an epidemiologist and cardiologist at Northwestern University's Feinberg School of Medicine, expressed concerns about potential side effects from booster shots. Specifically, she noted that cases of myocarditis, an inflammation of the heart, are more common after the second shot than the first, and added she was unsure whether the risks of a booster shot would outweigh the benefits for a healthy young person.

Further, Marion Pepper, an immunologist at the University of Washington, suggested that getting a booster shot too soon could have negative consequences.

Overstimulating the immune system can make it harder for your body to fight off some infections, Pepper said. She added that, while that hasn't been shown to happen with the coronavirus yet, it happens frequently with malaria. (LaFraniere, New York Times, 8/16; Sullivan, The Hill, 8/17; Cancryn et al., Politico, 8/17; Mandavilli, New York Times, 8/17; Gutman, The Atlantic, 8/17; Tribble, Kaiser Health News, 8/18; Herman, Axios, 8/18; Weixel, The Hill, 8/17; HHS statement, 8/18)