Experience with polyethylene glycol allergy-guided risk management for COVID-19 vaccine anaphylaxis

Background Polyethylene glycol (PEG) may elicit anaphylaxis to COVID-19 mRNA vaccines, and guidance for patients at risk is needed. Methods In retrospective patients with PEG allergy collected from 2006 till 2019, clinical, skin, and basophil activation test (BAT) characteristics discriminative for PEG allergy were analyzed and compared with the literature. In 421 prospective real-life patients asking for allergy workup for COVID-19 vaccine hypersensitivity in 2020/2021, risk assessment was performed and tolerance of the recommended vaccination approach was assessed. Results Ten patients with PEG allergy were found in the retrospective cohort. Patients reacted with immediate anaphylaxis (100%) not only to PEG-based laxatives/bowel preparations or injections, but also to cold medication, antiseptics, analgetics, or antibiotics. Skin tests +/- BAT with PEG +/- elicitors were positive in 10/10. Provocation tests were positive in 7/9 patients. From the prospective cohort, 370/421 patients self-reporting increased risk for vaccine allergy lacked criteria necessitating allergy workup and were recommended for routine vaccination. A total of 51/421 patients were tested, and three (6%) with PEG allergy were identified, whereas 48 patients remained negative in skin tests. Vaccination was recommended in all those patients. No hypersensitivity reactions were reported to vaccination including six PEG-allergic patients tolerating COVID-19 vaccination. Conclusions Taking a detailed history excluded PEG allergy in most referred patients and enabled direct safe vaccination. Immediate urticaria/anaphylaxis to typical elicitors identified patients requiring PEG allergy workup. Skin tests +/- BAT identified PEG allergy and helped to select the vaccine and the vaccination approach. Even PEG-allergic patients can tolerate COVID-19 vaccines.