COVID-19 boosters from Moderna Inc. and the partnership of Pfizer Inc. and BioNTech SE that are tailored to the latest omicron variants got U.S. regulatory clearance, a move toward additional protection as concern grows about potential new waves in the fall and winter.

The emergency use authorization is for use of a dose of Moderna’s shot in people 18 and older, while Pfizer’s can be used in people 12 and older, the Food and Drug Administration said Aug. 30 in a statement. The booster must be given at least two months after recipients’ latest COVID shot.

Advisers to the U.S. Centers for Disease Control and Prevention will meet Thursday and Friday, when they’re expected to discuss the shots, and Director Rochelle Walensky must give a recommendation before they’re administered nationwide.

Current vaccines are designed to prevent the Wuhan strain of SARS-CoV-2, but new mutants differ increasingly from the original version in ways that allow them to evade immunity afforded by shots and previous infections. The Biden administration has made plans to begin offering the new boosters as soon as the Labor Day weekend, Bloomberg reported last week.

“As we head into fall and begin to spend more time indoors, we strongly encourage anyone who is eligible to consider receiving a booster dose with a bivalent COVID-19 vaccine to provide better protection against currently circulating variants,” FDA Commissioner Robert Califf said in the statement.

Moderna shares rose 0.6% as of 10:39 a.m., Aug. 31, in New York. Shares of Pfizer were little changed.

New U.S. cases averaged about 88,000 in the seven days ending Aug. 29, according to the CDC, but hospitalizations and deaths have fallen as more people gain immunity through vaccination and earlier exposures to the virus. The redesigned booster shots are designed to provide immunity against omicron subvariants BA.4 and BA.5 — the versions of the virus that cause most of the world’s cases.

Thursday Vote

CDC’s Advisory Committee on Immunization Practices will hold a two-day meeting when members are expected to make their own recommendations about who should receive the shots. A vote has been scheduled for Thursday.

Pfizer and BioNTech are planning to file for authorization of an omicron-targeting vaccine for children 5 through 11 years of age in early October, according to a separate statement from the companies. They’re preparing an application for a similar vaccine in children 6 months through 4 years old.

The omicron-tailored boosters are likely to face a jaded public that is skeptical about their incremental benefits. Only 32% of the public has bothered to get a first booster dose, and fewer still have received fourth shots that have been available since the end of March.

Meanwhile, no human efficacy data yet show the benefit BA.4 and BA.5 tailored boosters will provide, as those trials are still ongoing at Moderna And Pfizer.

“I fear this vaccine is being oversold,” said Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, in an interview. “We have data in mice. We need human data. I don’t think that’s asking too much.”