PHILADELPHIA -- Federal health officials are expected to recommend that most Americans, regardless of age, get a COVID-19 vaccine booster shot. An announcement is expected as early as this week.
Sources tell CBS News and other news organizations that the recommendation would be for people to get the booster eight months after they receive the second dose of the Pfizer or Moderna vaccine. It is not clear what the guidance would be for those who got the Johnson & Johnson vaccine, as officials wait for more data to become available.
Last week, U.S. health officials recommended boosters for some with weakened immune systems, citing their higher risk of catching the virus and evidence that the vaccines' effectiveness waned over time.
Officials said the FDA would formally approve the vaccines before the boosters are administered widely. That action is expected for the Pfizer shot in the coming weeks. Currently, all three COVID-19 vaccines available in the United States are under emergency use authorization.
According to the New York Times, the first to report details of the government’s plans, health care workers, nursing home residents and emergency workers are likely to be the highest-priority recipients of the boosters. These were among the first people to be vaccinated, starting last December.
Since then, more than 198 million Americans have received at least one dose of a COVID-19 vaccine according to the Centers for Disease Control and Prevention, with more than 168 million fully vaccinated. Still, the country is experiencing a fourth surge of virus cases due to the more transmissible delta variant, which is spreading aggressively through unvaccinated communities but is also responsible for an increasing number of so-called "breakthrough infections" of fully vaccinated people.
Before reports about the boosters came out on Monday, Pfizer released Phase 1 clinical trial data on the third dose of its two-dose vaccine. In the trial, participants received a booster eight to nine months after their second dose.
"Results from this participant group show that the third dose elicited significantly higher neutralizing antibodies against the initial SARS-CoV-2 virus ... compared to the levels observed after the two-dose primary series, as well as against the Beta variant and the highly infectious Delta variant," the company announced in a press release.
Federal health officials have been actively looking at whether extra shots for the vaccinated would be needed as early as this fall. And there has been mixed messages on the need for boosters among the general public.
For months, officials said data still indicated that people remain highly protected from COVID-19, including the Delta variant, after receiving the two-dose Pfizer or Moderna regimen or the one-shot Johnson & Johnson vaccine. But U.S. health officials made clear Sunday they are preparing for the possibility that the time for boosters may come sooner than later.
"There is a concern that the vaccine may start to wane in its effectiveness," Collins said. "And delta is a nasty one for us to try to deal with. The combination of those two means we may need boosters, maybe beginning first with health care providers, as well as people in nursing homes, and then gradually moving forward" with others, such as older Americans who were among the first to get vaccinations.
He said because the Delta variant only started hitting the U.S. hard in July, the "next couple of weeks" of case data will help the U.S. make a decision.
Officials were continuing to collect information as well about the J&J vaccine, which was only approved in the U.S. in late February, to determine when to recommend boosters, one of the officials said.
The White House has said that even though the U.S. has begun sharing more than 110 million vaccine doses with the world, the nation has enough domestic supply to deliver boosters to Americans should they be recommended by health officials.
Global health officials, including the World Health Organization, have called on wealthier and more-vaccinated countries to hold off on booster shots to ensure the supply of first doses for people in the developing world.