The Food and Drug Administration on Wednesday authorized Pfizer-BioNTech COVID-19 booster shots for Americans 65 and older , those with high-risk conditions, and those in workplaces with high exposure risk but it stopped short of a similar push for the broader population.

Todays action demonstrates that science and the currently available data continue to guide the FDAs decision-making for COVID-19 vaccines during this pandemic, acting FDA Commissioner Janet Woodcock said in a statement. This pandemic is dynamic and evolving, with new data about vaccine safety and effectiveness becoming available every day. As we learn more about the safety and effectiveness of COVID-19 vaccines, including the use of a booster dose, we will continue to evaluate the rapidly changing science and keep the public informed.

The decision undercuts White House efforts to distribute boosters more widely as the highly contagious delta variant continues to spread, instead siding with a federal advisory panel that voted overwhelmingly last week against such a plan.

Data released by Pfizer last week shows the two-dose vaccine regimen remains highly effective against severe cases of the disease even as its protection against symptomatic cases has waned, falling from about 96% to 84% after six months.

Pfizer says a third shot would restore its effectiveness to about 95%.

The FDA signed off in August on a similar measure for immunocompromised people who are at higher risk for severe disease. But the agency stopped short of recommending boosters for otherwise healthy people who are fully vaccinated, signaling a need for more data.

In a nonbinding vote last week, an outside advisory panel assembled by the FDA ruled 16-2 against providing third shots to the general population.

I dont think a booster dose is going to significantly contribute to controlling the pandemic, said Dr. Cody Meissner of Tufts University, who sits on the panel. And I think its important that the main message we transmit is that weve got to get everyone two doses.

A handful of other countries, including Israel, Britain and Germany, have been offering boosters to more vulnerable segments of their population.

Last month, the head of the World Health Organization condemned plans to distribute additional doses in wealthy countries, calling for a moratorium. The shots would yield a far greater return if they were administered as first and second doses in developing nations, the WHO said, where new variants are more likely to emerge as the virus circulates more widely.

As weve seen from the emergence of variant after variant, we cannot get out of it unless the whole world gets out of it together, said Dr. Bruce Aylward, a WHO special adviser. And with the huge disparity in vaccination coverage, were simply not going to be able to achieve that.

Recipients of the Moderna and Johnson & Johnson COVID vaccines should stay tuned as the FDA weighs whether they will also need a booster.

Data released by Johnson & Johnson on Tuesday indicates the protection afforded by J&Js vaccine doesnt wane, unlike Pfizer and Modernas offerings, though a second shot would boost its efficacy against mild to severe COVID-19 from 74% up to 94%.