The FDA is investigating reports of allergic reactions to the Pfizer-BioNTech COVID-19 vaccine, according to The Washington Post.
Peter Marks, MD, PhD, director of the FDA's Center for Biologics Evaluation and Research, said Dec. 17 that allergic reactions were reported in more than one state, and it is looking into five different allergic reactions
"We are working hand in hand with the CDC and we've actually been working closely with our United Kingdom colleagues," Dr. Marks said, according to The Hill. "We'll be looking at all the data we can from each of these reactions to sort out exactly what happened, and we'll also be looking to try to understand which component of the vaccine might be helping to produce them."
Dr. Marks said the FDA is not certain what caused the reactions but said a chemical called polyethylene glycol may be at fault, according to the Post.
Two known allergic reaction cases involved healthcare workers at Juneau, Alaska-based Bartlett Regional Hospital. One worker had an anaphylactic reaction about 10 minutes after receiving the vaccine Dec. 15. The second worker reported eye puffiness, lightheadedness and a scratchy throat 10 minutes after receiving the vaccine Dec. 16.
In response to the reports of allergic reactions, the CDC released new guidelines Dec. 19 stating that people who have severe allergic reactions to the first COVID-19 vaccine dose should not get the second one. The agency also advises those who have had severe allergic reactions to other vaccines to consult their physician prior to getting the vaccine.