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F.D.A. to Authorize Third Vaccine Dose for People With Weak Immune Systems



Although the vast majority of Americans who have been vaccinated received Pfizer or Moderna shots, it was not immediately clear how those with immune deficiencies who received Johnson & Johnson shots were to proceed.

Understand the State of Vaccine and Mask Mandates in the U.S.

The F.D.A. decided not to broaden emergency use of the single-dose vaccine, at least in part because health officials wanted to see Johnson & Johnson’s clinical trial data on the safety and efficacy of two doses first, according to one official. Johnson & Johnson is expected to release the results of its two-dose study this month.

Some Biden administration officials are debating whether vulnerable segments of the general population will need booster shots to shore up their protection against Covid-19 — a decision that a number of scientists and public experts argue cannot be justified by current data.

Any such strategy would be based on a different risk-benefit calculus because the vaccines have proven extremely effective against severe disease or hospitalization for those without immune deficiencies. Some ordinary citizens are already seeking booster shots on their own, without waiting for an F.D.A. decision or a C.D.C. recommendation.

Dr. Dan Barouch, a virologist at Beth Israel Deaconess Medical Center in Boston who worked with Johnson & Johnson as it developed its vaccine, said the F.D.A.’s move to make third shots available to some with weakened immune systems made sense. But he said a similar approach could be attractive to physicians and patients: getting a different kind of vaccine altogether.

Dr. Barouch said there was a long and successful history of mixing and matching different vaccine platforms for other viruses. Because of the similarities in how coronavirus vaccines were produced, he said, mixing was particularly appealing, since it could potentially boost and broaden one’s immunity.

There is no data yet to determine whether protection against the virus is enhanced by such an approach, Dr. Barouch said. But researchers at the National Institutes of Health have a study underway that is expected to deliver some answers by early fall.

This content was originally published here.