Out of more than 4 million first shots of the Moderna vaccine administered, there were only 10 reports of serious allergic reactions, none of which were fatal, according to surveillance data from the Centers for Disease Control and Prevention.
All 10 vaccine recipients felt symptoms of anaphylaxis, or severe allergic reactions, within 30 minutes of getting the shots, according to a CDC report Friday. The agency determined the rate of anaphylaxis to be 2.5 cases per million Moderna COVID-19 vaccine doses administered, and eight of those 10 vaccine recipients were discharged from the hospital after a full recovery.
The report, which used data collected from Dec. 21, 2020, through Jan. 10, 2021, adds that five of those people who experienced allergic reactions had a history of experiencing such reactions in response to vaccines. Furthermore, eight of the vaccine recipients who had serious reactions to the Moderna shots fully recovered and were discharged home.
The CDC also found that the Pfizer-BioNTech vaccine, another mRNA vaccine and the first to be authorized for public use in the United States, had an anaphylaxis rate of 11.1 cases per million doses administered.
The agency concluded that “anaphylaxis after receipt of Moderna COVID-19 vaccine appears to be a rare event,” but data constraints due to the newness of the shots means that researchers can’t determine yet how the adverse effects compare to non-COVID-19 vaccines.
Still, Dr. Paul Offit, vaccine expert at the Children’s Hospital of Philadelphia and a member of the Food and Drug Administration’s panel on vaccines, told the Washington Examiner that reactions to the shots “are the side effects that one gets from a revved-up immune system.”
So far, roughly 18.4 million shots have been administered in the U.S. The Biden administration has pledged to inoculate 100 million people within 100 days.