4:22 p.m. ET, May 20, 2021
Fauci: "We don't know" when a booster vaccine may be needed
From CNN’s Virginia Langmaid and Michael Nedelman
The timeline for needing a booster shot is currently unclear, according to Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.
Despite predictions that a booster may be warranted within a year, the bottom line: “We don’t know,” Fauci told CNN Thursday.
His comments echoed ones he made earlier in the day to The Washington Post during a live event, when he said a rise in breakthrough infections may be the “trigger” for booster vaccinations, but it’s difficult to map out when that may happen.
“We're preparing for the eventuality that we might need boosters, but I think we've got to be careful not to let the people know that inevitably, X number of months from now, everyone's going to need a booster. That's just not the case,” Fauci said at the event. “We may not need it for quite a while.”
He also told the Post that immunity from vaccines may help avoid a surge in cases later this year.
If the US reaches President Biden’s goal of 70% of adults receiving their first shot by July 4, that may prevent cases from surging, “provided we continue to get people vaccinated at the rate we have now,” he said.
“I don't think we should be that concerned right now about how long they’re effective,” Fauci said. “I think they will be effective long enough that we will get to the point where we are not going to be necessarily worrying about a surge.”
These comments appear to contrast those made during an Axios interview Wednesday, when he said a booster could be warranted within a year’s time. Scientists at a number of companies that make Covid-19 vaccines have also predicted needing boosters within the same time frame – but the scientific community is not in widespread agreement on this.
“We’re making extrapolations” from incomplete data, Fauci explained to The Washington Post.
So far, studies have shown that mRNA vaccines – Pfizer and Moderna – maintain more than 90% efficacy six months after getting vaccinated. And scientists say it’s likely much longer; this is just as far as the data take us.
Other studies have looked at antibodies in the lab. While a decline is expected over time, Fauci told the Post “the steepness of that slope is unclear right now.”
Experts say it is also unclear how these antibody levels correlate with real-world immunity, and to what extent other parts of the immune system – such as T cells – could factor into this protection.