IgE-mediated allergy to polyethylene glycol (PEG) as a cause of anaphylaxis to mRNA COVID-19 vaccines.

Anaphylactic reactions to mRNA COVID-19 vaccines have been reported, with the polyethylene glycol (PEG) they contain being considered a possible culprit allergen. Sellaturay et al describe a patient who had a past anaphylactic reaction to a PEG-containing oral medication and urticarial reactions to topical application of PEG-containing personal care products, who subsequently had an anaphylactic reaction to the Pfizer/BioNTech mRNA COVID-19 vaccine.