ABSTRACT
Background: SARS-Cov- 2 is a new respiratory virus that causes COVID-19 disease. It is a new infectious agent and knowledge is still very limited, particularly its interaction with allergic disease. The aim of this study was to assess the effect of allergic disease on the risk of hospitalization for COVID-19. Method(s): A total of 7542 SARS-CoV- 2 infections were diagnosed from 1 March to 31 December 2020 at the Centro Hospitalar Universitario de Sao Joao. A total of 1727 (22.9%) patients were hospitalized (31% in intensive care) and 5815 were followed up by an outpatient clinic. Of this group, 3479 (65%) answered a telephone questionnaire, 3 to 6 months after acute infection, about sociodemographic, clinical, behavioral and psychological characteristics. They were also asked about a previous diagnosis of allergic disease. Individuals aged < 18 years and those with asymptomatic infection were excluded. Result(s): A sample of 2702 participants was analyzed, 33.5% reported allergic disease prior to the diagnosis of COVID-19: 215 (8%) asthma, 517 (19.2%) rhinitis, 138 (5.1%) drug allergy, 36 (1.3%) food allergy, 22 (0.8%) atopic dermatitis and 2 (0.1%) hymenoptera venom allergy. The proportion of participants with asthma is not statistically different across age groups, but when grouping other allergic diseases other than asthma, a reduction was observed with age (21.5% of 18-29 years old vs. 4.9 % with >=80 years, p > 0.001). Allergic disease was significantly more prevalent in women (asthma 9.8% vs. 5.2%;other allergies: 17.9% vs. 12.7%, p < 0.001). In a univariate analysis, the risk of hospitalization of patient with COVID-19 was significantly lower in those with allergic disease (OR = 0.7;95% CI: 0.55-0.92), but for asthma the effect was not significant. Gender was an interaction factor in this association, so in a separate multivariate model for women and men and adjusted for the other significant risk factors -age, obesity and comorbidities -the effect on risk reduction remained only in the men (adjusted OR = 0.6;95% CI:0.33-1.07). Conclusion(s): In this study, allergic disease, excluding asthma, was associated with a decrease in the severity of COVID-19, especially in men. However, further studies, namely prospective studies, are needed to better characterize this effect and the underlying mechanisms.