FDA restricts Johnson & Johnson COVID-19 vaccine due to blood clot risk

U.S. regulators on Thursday strictly limited who can receive Johnson & Johnson's COVID-19 vaccine due to the ongoing risk of rare but serious blood clots.

The Food and Drug Administration said the shot should only be given to adults who cannot receive a different vaccine or specifically request J&J's vaccine.

U.S. authorities for months have recommended that Americans starting their COVID-19 vaccinations use the Pfizer or Moderna shots instead.

FDA officials said in a statement that they decided to restrict J&J's vaccine after taking another look at data on the risk of life-threatening blood clots within two weeks of vaccination.

J&J's vaccine was initially considered an important tool in fighting the pandemic because it required only one shot. 

But the single-dose option proved less effective than two doses of the Pfizer and Moderna vaccines.

But follow-up studies have consistently shown lower effectiveness for J&J's vaccine. And while the blood clots seen with J&J's shot are rare, officials say they're still occurring.

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