The FDA and CDC advised the pause on Tuesday "out of an abundance of caution"
johnson & johnson covid vaccine
Johnson & Johnson's COVID-19 vaccine
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One day after the Food and Drug Administration and the Centers for Disease Control recommended a pause on inoculations with the Johnson & Johnson vaccine, all 50 states have opted to stop, switching instead to Pfizer or Moderna's COVID-19 vaccines.

The federal health agencies advised the pause on Tuesday "out of an abundance of caution," after they learned that six women between the ages of 18 and 48 had developed a rare blood clot condition called cerebral venous sinus thrombosis, or CVST, within two weeks of getting the Johnson & Johnson vaccine.

"I think the important thing to emphasize is that it is very rare," Dr. Anne Schuchat, the principal deputy director of the CDC, said on Good Morning America. "There was six women, out of the 6.85 million vaccinations of the J&J, which means that it's less than 1 in a million."

Schuchat confirmed that there is no evidence yet that the vaccine had caused the cases of CVST, and responded to the criticism that the FDA and CDC are raising alarm about an issue that is unlikely to occur at a time when people are already hesitant about the vaccines. She said that one of the main reasons for the pause was to communicate to physicians that CVST is a potential issue to look out for, and "to report it, because we don't know if we've missed some cases, whether the risk really is 1 in a million or possibly more than that."

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Speaking with Today, Dr. Anthony Fauci, the nation's top infectious diseases expert, said that he believes the pause on Johnson & Johnson vaccinations could actually reduce vaccine hesitancy.

"The very fact that you have an organization, two organizations, the CDC and the FDA, looking so carefully at this, making safety the primary concern, in my mind, confirms or underscores the situation that we take safety very seriously," Fauci said. "So I would think, at the end of the day, it could actually diminish hesitancy by saying, boy, those people there, they're looking at that really carefully. When they say something is safe, you can believe it is safe."

Fauci also said that people who have already received the Johnson & Johnson vaccine shouldn't "worry very much, because just as we've said, it is a very, very rare event."

"The bracket of time when this occurs was between 6 and 13 days. It is between one and two weeks," he told host Savannah Guthrie. "If you got your vaccine several weeks ago, then it makes it even less likely that you should have any concern at all. If you've had it within a few days, just stay heads-up for symptoms, severe headache, abdominal pain, chest pain, things like that."

"But again, underscoring, Savannah, it is a very, very rare event," Fauci added. "You don't want people who have just received the vaccine to be overly worried about this. This is a rare occurrence. The pause is just an abundance of caution to scope out the situation a little bit more closely."