COVID-19 vaccines: An allergological study

ABSTRACT

Background: In order to prevent infection with severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) an active approach is necessary. On December 2020 the commercialization of the COVID-19 vaccines was made. In Spain the first one to arrive was Pfizer-BioNtech vaccine. Initially, several reports of anaphylactic reactions due to the vaccine in the USA and in the UK were reported, which lead to an early recommendation to avoid the administration in patients with allergic history. The objective of this study is to describe and characterize the allergenic profiles of patients attended in our clinic for allergy testing to prevent reactions with the COVID-19 vaccine. Method: The allergological profile of 85 patients diagnosed with previous history of allergic disorders was analysed between January 18th and March 16th 2021. The allergological study included skin-prick test with polyethylene glycol (PEG), Tween 20, Tween 80, and COVID-19 vaccine (Pfizerâ), together with latex and other allergens when necessary. After the double dose of vaccine was completed, a follow up was done by telephone. Results: Risk stratification and approach is exposed in figure 1. Clinical and allergological characteristics of 85 patients are shown in table 1. Out of them, 88.2% had an allergic comorbidity and 48.2% had drug allergy. The reason for consultation was in 92.9% due to their allergic history, 76.5% were referred from the Occupational Health Service, and 80.6% of the patients have had previous vaccination with other anti-infective vaccines without reactions. Also, table 1 shows the prick-test results with COVID vaccine an its excipients, without any positive result. 70.7% of our population has completed the vaccination. Only 9 patients had a possible allergic reaction to the first dose, 8 of them had cutaneous and the remaining had respiratory symptoms. Out of these 9 patients, 6 had their second dose without any symptoms. Conclusion: None of the patients studied showed a positive test for neither the components of the vaccine nor the vaccine itself. More studies are required with a larger sample size to reach final conclusions. (Table Presented).