Hypersensitivity reactions to pfizer-biontech COVID-19 vaccine in the staff of Hospital Clínico San Carlos in Madrid, Spain

ABSTRACT

Background: The purpose of the study is to analyze the type of hypersensitivity reactions (HR) with Pfizer-BioNTech COVID-19 Vaccine (Comirnaty®) referred to our Allergy Department (AD), in order to asses vaccination with second dose safely. Method: Subjects with suspicion of HR after administration of first dose of Comirnaty® were referred to our AD from the Prevention and Occupational Risk Department responsible for the vaccination of hospital staff. Clinical history with special attention to atopic comorbidities and a detailed description of the HR after first dose of Comirnaty® was recorded. After providing signed informed consent, subjects underwent an allergy workup consisting of skin prick tests and intradermal tests (immediate and delayed readings) with polyethylene glycol (PEG) 4000 (1, 10 and 100 mg/ml), Polysorbate 80 (0.004 and 0.04 mg/dl), and Comirnaty® vaccine (as is). If skin tests proved negative, the second dose of Comirnaty® was administered under close supervision at our AD with an observation period of 60 minutes. Results: As of March 10, 2021, 6907 subjects had received the first dose of Comirnaty® and 5 were referred to our AD for evaluation. Mean age was 35 years, 4 were female and 1 male. Four patients had previous allergic history consisting of seasonal allergic rhinitis, contact dermatitis to nickel and thimerosal, and allergy to metamizole and mesalazine. After vaccination, two subjects had non-immediate reactions (NIR) that were generalized erythema within the first 48-96 h. Two subjects had immediate reactions (IR) 15 min after vaccination, consisting of generalized urticaria and erythema, and one was referred with a suspicion of immediate anaphylaxis but the reaction did not meet Brighton Anaphylaxis criteria. All subjects had negative skin tests with PEG-4000, Polysorbate 80 and Comirnaty®. The patient with the “suspicion of anaphylaxis” refused to receive the second dose. The remaining 4 subjects received the second dose of Comirnaty® with no reaction. Conclusion: The incidence of suggestive hypersensitivity reactions to Comirnaty® vaccine in our hospital staff was very low (0.07%). The administration of the second dose after a negative allergy workup seems safe, although the number of subjects treated is small.