key: cord-0781663-zoiwyo61
authors: Matsumoto, Kenji; Saito, Hirohisa
title: Does asthma affect morbidity or severity of Covid-19?
date: 2020-05-26
journal: J Allergy Clin Immunol
DOI: 10.1016/j.jaci.2020.05.017
sha: be2a6993a1a7475b388fa339d18f259aa2d266de
doc_id: 781663
cord_uid: zoiwyo61

nan

interesting results. Eight studies including a total of more than 17 thousand patients in 56 multiple geographic regions found that the comorbidity rates of Covid-19 with asthma were 57 significantly lower than the reported prevalence of asthma in the respective regions (Table   58   I ). In addition, two independent studies (Li X, et al.; Singer AJ, et al.) similarly 59 demonstrated that Covid-19 patients comorbid with chronic obstructive pulmonary disease 60 (COPD) or diabetes tended to be more severe, whereas those comorbid with asthma did not 61 (Table II) . However, there are several limitations to acknowledge in this hypothesis. All the 93 epidemiological data were obtained retrospectively or cross-sectionally, and no tests were 94 performed for IFN production or ACE2 expression in Covid-19 patients, especially those 95 comorbid with asthma. In addition, no detailed information was reported regarding the 96 phenotype/endotype (theoretically only T2-high, but not T2-low, asthma patients have low 97 ACE2 expression), lung function, control status or treatment regimen of the asthma patients. 98 We also do not know whether or not a diminished ACE2 expression level in asthma 99 patients actually reduces SARS-CoV-2 infections. Of note, a pair of recent studies using 100 clinical specimens reported that ACE2 mRNA expression in bronchial epithelial cells 9 and 101 in sputum 10 did not differ significantly between asthma patients and control subjects. These 102 findings differ from those of the aforementioned studies.

Finally, we would like to emphasize that this Editorial should not lead physicians to 

Covid-19: coronavirus disease 2019; COPD: chronic obstructive pulmonary disease