Pfizer Vaccine Ingredient PEG May Cause Anaphylaxis Key messages: The Pfizer/BioNTech COVID-19 vaccine can cause severe anaphylaxis of unknown cause Here, we show polyethylene glycol (PEG) allergy caused one of the first cases of anaphylaxis to the Pfizer/BioNTech COVID-19 vaccine Allergy skin prick testing with polyethylene glycol triggered anaphylaxis, highlighting […]