In response to the two cases of anaphylaxis in the United Kingdom, the MHRA issued a pause on vaccination with the Pfizer–BioNTech SARS-CoV-2 mRNA vaccine, to exclude any person with a history of anaphylactic reaction to any food, drug, or vaccine. The Centers for Disease Control and Prevention (CDC) has issued advice pertaining to administration of either the first or the second dose of the Pfizer–BioNTech or Moderna mRNA vaccine, recommending exclusion of any person who has a history of a severe or immediate (within 4 hours) allergic reaction associated with any of the vaccine components, including polyethylene glycol (PEG) and PEG derivatives such as polysorbates.3