About one in 400,000 recipients of the Moderna Inc. Covid-19 vaccine had a severe allergic reaction to the first shot, according to a study from the U.S. Centers for Disease Control and Prevention released on Friday.
The research, which tracked 10 cases of anaphylaxis among about 4 million doses administered through Jan. 10, concludes that such reactions to the vaccine still appear to be rare. Anaphylaxis to vaccines is uncommon but well-established -- with flu shots, for instance, it occurs about 1.3 times per million doses administered, according to CDC officials.
