Asthma, Severe Acute Respiratory Syndrome Coronavirus-2 and Coronavirus Disease 2019

Dylan T. Timberlake; Kasey Strothman; Mitchell H. Grayson


Curr Opin Allergy Clin Immunol. 2021;21(2):182-187. 

In This Article

Coronavirus Disease 2019 and Asthma

Although the current data on asthma and COVID-19 are almost exclusively retrospective, and have obvious limitations, they strongly suggest that asthma is not a risk factor for severe COVID-19 and that SARS-CoV-2 does not exacerbate asthma. Initial epidemiology reports from Wuhan, China failed to include asthma in the list of comorbid conditions of hospitalized COVID-19 patients.[31] Further reports from China listed asthma as a comorbidity in only 0.3–0.9% of patients admitted with COVID-19.[32,33] This rate of asthma is markedly lower than the 1.4% published prevalence of asthma in China.[34] The lower prevalence of asthma in hospitalized COVID-19 patients was seen outside of China, as well. Data from a pediatric Italian cohort revealed that only 2% of inpatient COVID-19 patients had asthma,[35] whereas the national asthma prevalence is 6.63%.[36] In Spain, 5.2% of patients admitted with COVID-19 had asthma,[37] which is similar to the prevalence of asthma in Spain, ranging from 5 to 14.5% depending upon location.[38] Lastly, in New York, between 9 and 12.6% of admitted COVID-19 patients had a diagnosis of asthma,[39,40] which is higher than the point prevalence of asthma in the United States (7.6%).[41] However, these retrospective chart reviews included any patient with a documented history of asthma, and thus it would be more appropriate to compare the rates of asthma among admitted patients to the 13.6% lifetime prevalence of asthma in the United States.[41] When using lifetime prevalence of asthma, once again the prevalence of asthma among admitted patients with COVID-19 is similar to or decreased compared to the general population.

Multiple studies have demonstrated no increased severity of disease among admitted COVID-19 patients with asthma. A study of a Chinese cohort indicated that asthma was not associated with severe disease,[33] whereas a Spanish cohort showed patients with asthma had no different risk of mortality compared to those without asthma.[37] In two studies in New York, the presence of asthma was found to have no effect on COVID-19 length of stay, intubation, readmission, or mortality.[40,42] Similarly, a study of patients in a Seattle ICU found a prevalence of asthma of 14%,[43] which again is similar to the lifetime prevalence of asthma in the United States (13.6%).[41] In a South Korean study, asthma was found to impart a small increased risk of severe disease (OR 1.08, CI 1.01–1.17), which was defined as ICU admission, invasive ventilation, or death. However, once stratified into allergic asthma (asthma with comorbid allergic rhinitis or atopic dermatitis) or nonallergic asthma, allergic asthma demonstrated no increased risk of severe outcomes (OR 1.40, CI 0.83–2.41). Nonallergic asthma demonstrated a markedly increased risk of severe disease (OR 4.09, CI 1.69–10.52).[44] Overall, these retrospective reviews suggest that asthma is not associated with increased rates of admission from COVID-19 and that asthma is not a risk factor for severe disease (Figure 1). However, there are no data demonstrating that asthma protects from severe COVID-19 disease.