ABSTRACT
Background: Adverse reaction's reported after COVID 19 vaccination had a negative impact on public opinion. These adverse reactions may be or may be not be mediated by hypersensibility reactions. The proper assesment and the manegament of adverse reactions are crucial in order to offer a safer inmunitation and also to reduce the misinformation and the growing rejection to COVID 19 vaccination. Objective(s): To describe clinical characteristics and the allergological study done in different patients who had an adverse event right after COVID 19 vaccine administration Method: Descriptive study in patients who have experienced an adverse event after one single dose of the SARS CoV2's vaccine. Sex, age, atopy, drug allergies, anaphylaxis reaction (according to EEACI), syntoms, timing, vaccine and dose are described on this study. Skin test were done in every patient (Prick-Test and intradermo reaction) with ARN vaccine samples (Pfizer and Moderna), Adenovirus vaccine extract (Astrazeneca) and a battery of excipients (Polietilenglicol, Polisorbato80 and Trometamol). Result(s): The study included 44 patients with an average of 48,76 +/- 12,23 years, (93% women-29% atopic). 29% of the patients reported to be allergic to other drugs (AINES especially). The most frequent reaction according to EEACI anaphilaxy's classification was Grade 1 with a 61%. Grade 2: 18%, Grade 3: 21%. Urticaria and/or angioedema were the most frequent syntoms (60%) followed by disnea (20%) and being late syntoms (50%) the most usual ones. Pfizer was the most implicated vaccine (64%) with the first dose (84%). Skin tests with Polietilenglicol, Trometamol and Polisorbato80 at different concentrations were negative in all patients but two, one positive to Polisorbato80 0.004mg/ml with a previous sensitization to Prontosan (contains Polisorbato) and another one positive to Trometamol 0.1mg/ml. Conclusion(s): Allergists play a main role to offer the maximum befenits to their patients and to improve the vaccine's safety. Skin tests were the most efective tool to diagnose hypersensibility reactions. The 93,17% of the patients with a negative test result tolerated the second dose. The others did not get the second dose due to their own will. Avoiding the COVID 19 vaccine was recommended in those patients with a hypersensibility to the vaccine components diagnose.