Cross-Reactivity between Pfizer/BioNTech and Johnsson Vaccines: A Case Report: An International Journal of Medical Toxicology and Drug Experience

ABSTRACT

Introduction: Polyethylene glycol (PEG) is one of the ingredients in the Pfizer/BioNTech COVID 19 vaccine (mRNA vaccine) and has been known to cause hypersensitivity [1-3]. Polysorbate is an ingredient in the Johnson vaccine (adenovirus vaccine) which may crossreact with PEG. Objective: We report a case of cross-reactivity between Pfizer/ BioNTech and Johnsson vaccines. Methods: This observation was notified in the pharmacovigilance center of Sfax, Tunisia (faculty of medicine of Sfax). The study of drug imputability was carried out according to the WHO method. Results: We report the case of a 32-year-old Tunisian woman with a history of atopy and intolerance to non-steroidal anti-inflammatory drugs (NSAIDs) but no history of SARS-CoV-2 infection. On August 15, 2021 (at 0830), she developed sweating, vomiting and dizziness immediately after receiving the initial dose of Johnson COVID-19 vaccine. Her blood pressure became lower (less than 90/60 mmHg). She had to stay at the vaccination centre for one hour, and the clinical signs improved spontaneously after one hour. In the evening of the same day, the patient presented a febrile maculopapular eruption in the abdomen, trunk, and face. The rash resolved spontaneously over a week. The patient was referred to the pharma-covigilance center of Sfax (Tunisia). The messenger RNA vaccine was advocated for the second vaccine. On December 2021, she was received the second dose of the Pfizer/BioNTech COVID 19 vaccine (mRNA vaccine). Six hours later, she experienced a pruritic maculopapular rash on the abdomen, trunk, neck, and face. These clinical signs improved spontaneously after two days. the diagnosis of cross-allergy between these two vaccines was retained for this patient Conclusion: To our knowledge, this is the first cross-allergy between mRNA and adenovirus COVID-19 vaccines notified in Tunisian population. Healthcare professionals should be aware that hypersen-sitivity can occur with COVID-19 vaccines containing macrogols/ PEGs and those containing polysorbates. Its recognition may be challenging and often require skin testing. Per CDC guidance, con-sultation with an allergist-pharmacologist should be considered to help determine if the patient can safely receive vaccination [4].