Tthe Modern Covid-19 vaccine, like the one made by Pfizer and BioNTech, appears to cause rare anaphylactic reactions in a small number of people receiving the vaccine, according to new data from the Centers for Disease Control and Prevention.
As of Jan. 19, there were 15 confirmed cases of anaphylaxis after receiving Moderna’s vaccine and 45 confirmed cases of anaphylaxis after receiving the Pfizer vaccine, the CDC said in a statement to STAT. According to the agency, this is a rate of 2.1 cases per million doses of the Moderna vaccine and 6.2 cases per million doses of Pfizer.
Anaphylaxis is a serious allergic reaction that can be life-threatening if not treated quickly.
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Early monitoring of both Moderna and Pfizer BioNTech Covid-19 vaccines indicates that anaphylaxis after vaccination is a rare occurrence, and although anaphylaxis is serious, it occurs shortly after vaccination (usually within minutes). easily diagnosed and effective treatments available, ”the agency said in an email.
It noted that the rate at which anaphylaxis is reported after vaccination is likely to change as more vaccine doses are given. In fact, they already have. The first report on US cases of anaphylaxis after administration of the Pfizer vaccine suggested that it occurred at 11.1 cases per million doses.
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In a report published Friday on cases of anaphylaxis among people who received the Moderna vaccine between December 21 and January 10, the CDC set out ten cases, all of which occurred in women. During the study period, more than 4 million doses of the Moderna vaccine were administered.
In Friday’s report, six of the ten people who contracted anaphylaxis were admitted to hospital and four of them had to be intubated to facilitate their breathing. None of the people were killed, the CDC reported. To date, there have been no reports of fatal cases of anaphylaxis associated with Covid vaccines in the United States.
All ten people who developed anaphylaxis received epinephrine, the drug in EpiPens that is used to combat severe allergic reactions. The CDC said those administering Covid vaccines should be equipped to treat anaphylaxis, including epinephrine injections on hand.
Anaphylaxis occurred rapidly in the affected people, with the median time to onset of symptoms being 7.5 minutes. People receiving Covid-19 vaccines are supposed to monitor for 15 minutes after the injection, and the period is extended to 30 minutes for people with a history of severe allergies or anaphylaxis.
Nine of the ten people had a history of allergies and five of them had previously experienced an anaphylactic reaction.
This story has been updated with additional data and comments from the CDC.