The Centers for Disease Control and Prevention (CDC) issued new guidelines on Saturday to address reported severe allergic reactions to the coronavirus vaccine.
The agency said it recently “learned of reports” of some people experiencing severe allergic reactions after getting inoculated. The agency defined a “severe reaction” as one where a person needs to be treated with epinephrine or requires hospitalization.
The CDC said that people who have a severe allergic reactions after the first dose should not get the second shot.
Those who have had severe allergic reactions to a component in a COVID-19 vaccine should not get that specific vaccine.
The agency also advises those who have had severe allergic reactions to other vaccines or therapies consult their doctor before getting inoculated. However, people with a history of severe allergic reactions not related to vaccines or injectable medicines may still get vaccinated, the CDC said.
The guidelines come after the Food and Drug Administration (FDA) said it was looking into five severe reactions to Pfizer’s vaccine reported this week. Two reactions were reported in Alaska, and the others have been reported in other states.
Peter Marks, who leads the agency’s Center for Biologics Evaluation and Research, told reporters that the agency wasn’t sure what caused the reaction, but said a chemical called polyethylene glycol, which is present in Pfizer and Moderna’s coronavirus vaccine, “could be the culprit.”
The agency said Friday that people with a history of severe allergic reactions to any component of the vaccine should avoid getting inoculated.
The U.K.’s Medicines and Healthcare Products Regulatory Agency warned earlier this month that people with “significant” histories of allergic reactions should avoid getting Pfizer’s vaccine, after two people reported adverse reactions.