The U.S. Food and Drug Administration is nearing a decision to authorize Covid-19 booster shots for certain people with weak immune systems, people familiar with the matter said, a shift in the American vaccination strategy as the Delta variant drives up cases of infection.
The agency could make a decision as early as Thursday and probably by Friday, one of the people said.
The agency is closing in on the booster-shot authorization amid evidence that vaccines are less effective protecting immunocompromised people from Covid-19 than they are in protecting the general population.
Some public health experts and vaccine makers have also recommended boosters as necessary for broader swaths of the population to keep strong protection against newer variants of the coronavirus, and because some preliminary research indicates vaccines may lose effectiveness over time.
The Biden administration is expected to lay out a plan for boosters by early September.