Asthma and COVID-19: an update

Abstract

As the world faces the coronavirus disease 2019 (COVID-19) pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, concerns have been raised that asthma patients could be at increased risk of SARS-CoV-2 infection and disease severity. However, it appears that asthma is not an independent risk factor for both. Furthermore, asthma is not over-represented in hospitalised patients with severe pneumonia due to SARS-CoV-2 infection and there was no increased risk of asthma exacerbations triggered by SARS-CoV-2. There is accumulating evidence that asthma phenotypes and comorbidities are important factors in evaluating the risk for SARS-CoV-2 infection and disease severity, as findings suggest that Th2-high inflammation may reduce the risk of SARS-Cov-2 infection and disease severity in contrast to increased risk in patients with Th2-low asthma. The use of inhaled corticosteroids (ICS) is safe in asthma patients with SARS-CoV-2 infection. Furthermore, it has been proposed that ICS may confer some degree of protection against SARS-CoV-2 infection and the development of severe disease by reducing the expression of angiotensin converting enzyme-2 and transmembrane protease serine in the lung. In contrast, chronic or recurrent use of systemic corticosteroids before SARS-CoV-2 infection is a major risk factor of poor outcomes and worst survival in asthma patients. Conversely, biological therapy for severe allergic and eosinophilic asthma does not increase the risk of being infected with SARS-CoV-2 or having worse COVID-19 severity. In the present review we will summarise the current literature regarding asthma and COVID-19.

FIGURE 1

Asthma medications and the risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and disease severity. COVID-19: coronavirus disease 2019; ICS: inhaled corticosteroids; SCS: systemic corticosteroids.

FIGURE 2

Association of oral corticosteroids use and outcomes in asthmatic patients with coronavirus disease 2019 (COVID-19). Reproduced from Adir et al. [30]. a) Adjusted^# hazard ratios (HRs; 95% CI) for the association oral corticosteroids (OCS) use in the prior year and the composite of moderate to severe COVID-19 or all-cause mortality within 90 days following PCR date among adult asthmatic patients with positive PCR for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (n=8242). OCS use refers to any use in the year before baseline with no OCS use serving as reference category. b) Adjusted^# HRs (95% CI) for the association recent and former OCS use and the composite of moderate to severe COVID-19 or all-cause mortality within 90 days following PCR date among adult asthmatic patients with positive PCR for SARS-CoV-2 (n=8242). c) Adjusted^# HRs (95% CI) for the association between the number of filled steroids prescriptions in the prior years and the composite of moderate to severe COVID-19 disease and all-cause mortality within 90 days following PCR date among adult asthmatic patients with positive PCR for SARS-CoV-2 (n=8242). ^#: adjusted for age, sex, ethnicity, diabetes, hypertension, ischaemic heart disease, obesity, smoking and biologics use.