COVID-19 Susceptibility in Bronchial Asthma

Background: Bronchial asthma has not been adequately assessed in coronavirus disease 2019 (COVID-19). Respiratory allergy is associated with significant reductions in the expression of angiotensin-converting enzyme 2 receptor, which is the entry receptor for COVID-19. Objective: To observe COVID-19 susceptibility in patients with bronchial asthma, analyze the prevalence of asthma in a large cohort of consecutive outpatient subjects who were tested with the RT-PCR assay for COVID-19. Methods: This was a retrospective population-based cross-sectional study using data from a large nationwide health maintenance organization in Israel. All health maintenance organization enrollees who had been tested for COVID-19 from February to June 2020 were included. Differences in demographic and clinical characteristics between the subjects with negative and positive COVID-19 RT-PCR test results and between COVID-19 RT-PCR–positive subjects with and without asthma were analyzed. Results: A total of 37,469 subjects were tested for COVID-19 RT-PCR, and results for 2,266 (6.05%) of them were positive. A significantly higher proportion of smokers was observed in the COVID-19–negative group than in the COVID-19–positive group (4734 [13.45%] vs 103 [4.55%]; P <.001). Asthma was found in 153 (6.75 %) subjects of the COVID-19–positive group and in 3388 (9.62%) subjects of the COVID-19–negative group (P <.001). No significant impact of antileukotrienes, inhaled corticosteroids, and long-acting beta-blockers use was revealed on COVID-19 positivity proportions. Multiple logistic regression analysis adjusted for sex, age, smoking, and comorbidity revealed a negative association of asthma with the likelihood of being positive for COVID-19 (odds ratio, 0.71; 95% CI, 0.58-0.87; P =.001). Conclusions: We observed lower COVID-19 susceptibility in patients with preexisting asthma.