Patients with previous immediate hypersensitivity reactions to polyethylene glycol can safely receive the BNT162b2 mRNA COVID-19 vaccine.

Previous anaphylaxis or immediate allergic reaction to polyethylene glycol (PEG; also known as macrogol) is considered a contraindication to the BNT162b2 mRNA COVID-19 vaccine, which contains 50 ug of PEG at a molecular weight of 2000, and this component is thought to account for the higher rate of anaphylaxis seen with this vaccine (4.7 per million doses) than with other non-mRNA vaccines. However, there is evidence that both anaphylaxis to PEG and anaphylaxis to the Pfizer COVID-19 reaction may not be IgE-mediated, with patients with anaphylaxis to first dose of the Pfizer COVID-19 vaccine receiving their second dose of vaccine without no or milder reactions in a high-risk clinic setting.

Penicillin Allergy De-labeling Results in Significant Changes in Outpatient Antibiotic Prescribing Patterns.

Unverified penicillin allergies are common but most patients with a penicillin allergy label can safely use penicillin antibiotics. Penicillin allergy labels are associated with poor clinical outcomes and overuse of second-line antibiotics. There is increasing focus on penicillin allergy "de-labeling" as a tool to improve antibiotic prescribing and antimicrobial stewardship.