Anti-COVID-19 vaccine late hypersensitivity reaction

ABSTRACT

Background: First approved anti-COVID vaccines brought a new experience of hypersensitivity reactions into clinical practice. This experience and knowledge of mechanisms are important for further safer and wider use of these immunizations. Methods: Clinical and laboratory data collected in immunoallergology outpatient evaluation and consultation of informatic process. Written consent was obtained. Results: We report a case of a 33-year-old woman, a laboratory worker, who received the first dose of mRNA-based anti-COVID-19 vaccine. After 48-72h she presented with extensive generalized urticaria lesions and pruritus. She was admitted to the emergency department, treated with endovenous corticosteroid and antihistaminic, attenuating skin lesions. However, 12-24h later, urticaria exacerbated, with labial and bilateral ear swelling. She was medicated with oral prednisolone, gradually resolving symptoms. She had no concomitant alcohol/ drug consumption nor practiced physical exercise. She had antecedents of persistent allergic rhinitis and allergic bronchial asthma in the first step of treatment. She had no prior history of drug allergy nor adverse reactions to vaccines. Skin prick tests performed with commercial extracts of aeroallergens were positive for D. pteronyssinus, D. farinae, lepidoglyphus, olive tree pollen, grass pollen, and cat and dog dander. Skin prick test with latex was negative. Basal tryptase was 6.4 and total IgE 154.0 UI/mL. Spirometry was normal at basal condition. Prick test with anti-COVID-19 vaccine was negative. Intradermal test with 1/100 and 1/10 dilutions of anti-COVID-19 vaccine was also negative at 20-30 minutes. However, after 4h she showed hyperemia and swelling of about 7-8cm, localized at the place of both dilutions of intradermal test vaccine administration. PATCH tests performed with anti-COVID-19 vaccine were negative at 48h and 72h readings. She was diagnosed with anti-COVID-19 vaccine late hypersensitivity and, therefore, was not able to take the second dose. Discussion: We report a clinical case of late hypersensitivity to mRNA-based anti-COVID-19 vaccine in a patient without prior history of drug allergy. The reaction was documented with positive intradermal tests performed with 1/100 and 1/10 vaccine dilutions. According to EAACI indications, she did not receive the second dose of the vaccine. Extracts of vaccine components will help to understand adverse reactions and choosing an alternative vaccine, when available.