Shots could become available in mere days.

The supplements to Pfizer’s and Moderna’s initial jabs are known as “bivalent” boosters, as they’ll target both BA.4 and BA.5—two Omicron variants currently dominating the U.S. and much of the world. They will offered continued protection against original COVID strains as well.

“You’ll see me at the front of the line,” FDA vaccine chief Dr. Peter Marks told The Associated Press shortly before Wednesday’s announcement.

The Moderna booster is authorized for those 18 and older, while the Pfizer booster is authorized is for those 12 years and older. Those who’ve completed the initial two-part COVID vaccine and are at least two months out from it—or two months out from their last booster—are eligible, according to FDA officials.

Younger individuals will likely become eligible in the next month or two, once vaccine manufacturers submit data regarding those age groups, officials added.

The U.S. Centers for Disease Control must still make further recommendations as to who should get the new jab, and in what order of priority. A panel is set to convene on the matter Thursday.

U.S. life expectancy dropped again last year for the second year in a row, to the lowest level since 1996, according to a provisional report released this month by the National Vital Statistics System.

COVID was the leading contributor to the decline.

“This is a remarkable opportunity to improve our life expectancy and reduce the toll of mortality in our population,” Dr. Robert Califf, FDA commissioner, said at a Wednesday press conference on the boosters’ approval.

The original vaccine offers poor protection against symptomatic disease from BA.5, Marks said, adding that new boosters allow individuals to “refresh the immune system with what is actually circulating.”

For those who’ve never received a booster, the new jab will likely reduce their risk of getting long COVID by more than half, Marks said.

Preemptively flattening the curve

The updated boosters come ahead of an anticipated fall surge of COVID, with a projected peak around Dec. 1, Marks said. The new boosters have the potential to lower currently plateaued levels of COVID and pre-emptively flatten the coming curve.

The U.S. could see 100 million COVID infections this fall and winter—and potentially a sizable wave of deaths, the White House warned in May.

BA.5 comprised nearly 89% of U.S. COVID cases last week, according to CDC data released Tuesday. BA.4.6, a spin-off of close BA.5 relative BA.4, comprised 7.5% of cases, while BA.4 comprised 3.6% of cases. BA.2.12.1, dominant in the U.S. earlier this spring and summer, comprised less than a quarter of 1% of cases.

Whatever variant or subvariant fuels cases later this year, the hope is that it will be more similar to BA.4 and BA.5 than the original strain, so that the new boosters continue to offer increased protection, FDA officials said Wednesday.