A health care worker in Alaska had a serious allergic reaction after receiving the Pfizer vaccine.
Officials say that person is now in stable condition.
The FDA says most Americans should be okay to take the vaccine, even if they have allergies.
But keep this in mind: if you've had past reactions to vaccines or if you're are allergic to certain ingredients in this one, you should not get the shot.
Last week, two health care workers in the U.K. had allergic reactions to the vaccine.