Immune-mediated reactions to Sars-Cov-2 vaccine: the experience of an immunology outpatients facility

ABSTRACT

Background and Aim of the study SARS-CoV2 vaccines may cause immune-mediated reactions with different mechanisms, the main being immediate and delayed hypersensitivity, dis-immune mechanisms due to Spike protein molecular mimicry and autoimmune pathogenesis. In July 2021 a new Immunology outpatients facility was inaugurated in Cardarelli Hospital - Naples, in order to respond to the increasing demand of immunological consult. Materials and Methods: We accessed our outpatients clinical files by selecting the patients with suspected immune-mediated reaction to SARS-CoV2 vaccines. We reported sex, reaction type, vaccine type, time of onset, duration, treatment, clinical outcome, result of poly-ethylene-glycole (PEG) testing, indication for continuation of vaccine program and, for 'autoimmune-like' reactions, final diagnosis and treatment. Results: Nine women reported hypersensitivity reactions with mRNA vaccines. All the subjects were skin tested for PEG the test was positive in 5 patients, who were suggested to be vaccinated with desensitization protocol, while the other 4 underwent subsequent doses with previous anti-histamine/steroid treatment. Six patients - 5 women and 1 man - reported 'autoimmune-like' reactions 3 have been diagnosed for Indifferentiated Connectivitis and 1 for Behcet flare. These data will be updated. Conclusions: The increasing numbers of suspected immune-mediated reactions to vaccines detected in our clinical practice show the need of empower Clinical Immunology facilities in order to improve the safety of the vaccinated population.