The relationship between coronavirus disease 2019 and atopy

Aim: In the current thesis, the possibility of Coronavirus Disease 2019 (COVID-19) triggering an allergic response was examined. In this context, the effects of COVID-19 and its vaccines on total and specific IgE (milk and egg) were measured with the ELISA test kits we developed. Material and Method: Four experimental designs were constructed retrospectively to investigate: (1) The effect of the time after COVID-19 (first 4 months, n=361), (2) The effect of allergic history in people with COVID-19 (n=61), (3) the effect of COVID-19 symptom severity (n=66) and (4) the effect of COVID-19 vaccines (n=178) on IgE levels. Total and specific (anti-SARS-CoV-2) IgG levels were also measured. Results: The mean anti-SARS-CoV-2 IgG levels were higher than the cut-off value. While the total IgE level after COVID-19 was high in the first month (p<0.05), specific IgE levels (egg white and yolk) increased after the 2nd month (p<0.05). Allergic history and COVID-19 severity increased total IgE (p<0.05) but did not affect specific IgE levels (P>0.05). Vaccination increased total IgE (only allergic individuals) and specific IgE against egg yolk (only allergic individuals) and egg white (p<0.05) but it did not affect milk specific IgE (p>0.05). Conclusion: COVID-19 and its vaccines increased total and egg-specific IgE levels revealing associations between SARS-CoV-2 and egg allergy. However, this was not the case for milk allergy, most likely due to epitope similiarity between egg allergens and the SARS-CoV-2 virus. Moreover, increased total IgE in individuals with severe COVID-19 may support anti-IgE treatments to decrease its severity. Keywords: Allergy, Anti-SARS-CoV-2 IgG, COVID-19, IgE, IgG