Americans may be able to receive the next Covid shots as early as Wednesday, the last of a trifecta of vaccines intended to prevent respiratory infections this fall and winter.
On Monday, the Food and Drug Administration authorized updated Covid vaccines by Pfizer and Moderna. A scientific advisory committee to the Centers for Disease Control and Prevention will meet on Tuesday to review the data and make more specific recommendations about who should get the shots and when.
“I expect them to come out and recommend it for everyone,” said Dr. Ashish Jha, dean of the Brown University School of Public Health, who served as the White House’s Covid czar until June.
Large pharmacies will most likely have vaccines on offer later this week, assuming Dr. Mandy Cohen, the new C.D.C. director, signs off on the recommendations.
For some Americans, the vaccines cannot come soon enough. Hospital admissions and deaths associated with Covid have been steadily rising since July, although the numbers are still low compared with the same period in recent years.
But many others now view Covid as only a mild threat. Fewer than half of adults older than 65, and just about one in five American adults overall, opted for the bivalent booster shot offered last fall.
Vaccines against flu and the respiratory syncytial virus are already available. The flu vaccine is recommended for everyone 6 months and older, and the R.S.V. vaccine for everyone 60 and older, in consultation with a health care provider.
The most vulnerable — older adults, immunocompromised people and pregnant women — should receive both the Covid and flu vaccines, experts said.
Adults 65 and older accounted for up to 85 percent of flu-related deaths in recent years, according to the C.D.C. Those 75 and older also account for the vast majority of hospitalizations and deaths from Covid.
The C.D.C.’s advisers will need to decide whether to recommend the new Covid vaccines for younger people who have built up strong immunity through previous shots or infections. (The F.D.A. has authorized the shots for almost everyone, but the C.D.C. makes the recommendations on clinical use.)
Officials in Britain are offering the new Covid vaccines only to those at high risk, including older adults, those with chronic medical conditions and frontline workers. But that decision was made not because of a calculation about who would most benefit, but because of the prohibitive costs to the British government of offering the shots to everyone, Dr. Jha said.
As with the flu vaccine, the greatest benefits of Covid immunization may accrue to those at highest risk. Nonetheless, the shots may help even those with reduced risk recover sooner after an infection, or miss fewer days of work, Dr. Jha said.
And even among the relatively young and healthy, Covid poses risks that are harder to define, including long-term effects on the heart and long Covid. “I don’t want to diminish the tragedy of younger people who may be hospitalized,” said Gigi Gronvall, a biosecurity expert at the Johns Hopkins Center for Health Security.
The shots will be available for free to most Americans through private insurers and through a new federal program for uninsured people.