fb-pixel Skip to main content

The “overwhelming majority” of vaccinated Americans should get COVID-19 booster shots, the nation’s top infectious disease expert said Tuesday, as the United States faces a rise in COVID-19 cases and hospitalizations and a surge in holiday travel.

“We’d like to get as many people who were originally vaccinated with the first regimen boosted,” Dr. Anthony Fauci said in an interview with Reuters.

The Centers for Disease Control and Prevention last week expanded the availability of boosters to all adults and recommended them for people 50 and older. As of Wednesday, about 36.6 million Americans have received the shots, or about 18.7 percent of the population, including about 19.5 million recipients age 65 or older, according to CDC data.


Fauci’s comments come as infections are rising in the US and particularly in New England. The seven-day daily average of COVID-19 cases nationally is about 92,800 per day, Dr. Rochelle Walensky, the CDC chief, said during a White House COVID-19 briefing on Monday, an 18 percent increase from the previous week while the seven-day average of hospital admissions is up about 6 percent. Over the past two weeks, the seven-day average of new cases has increased by 83 percent in Massachusetts and 59 percent across New England.

Fauci added that officials are considering whether the definition of “fully vaccinated” will be amended to include booster doses — three doses of an mRNA vaccine like those made by Pfizer and Moderna, and two doses of the Johnson & Johnson vaccine.

“Right now, officially, fully vaccinated equals two shots of the mRNA and one shot of the J&J, but without a doubt that could change,” he said. “That’s on the table for discussion.”

Multiple infectious disease experts said they anticipate boosters becoming part of the standard COVID-19 vaccine regimen — just not right away. They also stressed that a more pressing matter is changing the course of the pandemic by ensuring the millions of Americans who are not yet vaccinated get their shots.


“What I do foresee is that in the future, the mRNAs are probably going to be three shots,” said Dr. Sabrina Assoumou, an infectious disease physician at Boston Medical Center and professor at Boston University School of Medicine. “If you take, for example, Pfizer — you’ll have the three weeks and then you’ll have the third shot six months later, because we know that it offers a better outcome by doing it that way.”

As for those who received the one-dose Johnson & Johnson vaccine, for whom boosters are recommended by the CDC at least two months after the shot, Assoumou said she anticipates they will be considered fully vaccinated once they have had a second shot.

“I think with J&J ultimately to be considered fully vaccinated, you’re going to need that extra shot,” Assoumou said. “We’d hoped that it was only going to be just a one-shot deal, especially for people who really wanted an option with just one shot.”

Amanda Kaufman can be reached at amanda.kaufman@globe.com. Follow her on Twitter @amandakauf1.