Inhaled Steroids in Asthma during the COVID-19 Outbreak

March 18, 2020

Inhalde steroids for asthma appear to be safe

Jamie Hartmann-Boyce, Richard Hobbs

Are inhaled steroids in asthma OK to use or should you discontinue them?

Verdict: There is no evidence of a relationship between the use of inhaled corticosteroids and COVID-19 infection at present. Inhaled corticosteroids are generally considered a safe and frontline treatment for controlling asthma symptoms. Evidence from a 2013 systematic review of seven randomized controlled trials found that discontinuing inhaled corticosteroids in people with stable asthma more than doubled the risk of asthma exacerbation (RR 2.35, 95% CI 1.88 to 2.92, mean follow-up 27 weeks). Inhaled corticosteroids, when taken as prescribed, would reduce the risk of an asthma attack being triggered by a respiratory virus such as COVID-19. There is uncertainty over whether the prescription of higher dose increases the risks of pneumonia.

There is evidence that inhaled steroids increase the risks of (some) respiratory infections in people with asthma

A 2019 systematic review of 17 randomized controlled trials in people with asthma ( n = 15,336) found that Inhaled corticosteroid treatment (ICS) was associated with a significantly increased risk of upper respiratory tract infections (Odds ratio R 1.24, 95% CI 1.08 to 1.42). There was minimal statistical heterogeneity despite the fact the studies included a range of doses and treatments and used a range of different definitions of upper respiratory tract infection. When subgroup analyses were performed for high- and low- dose ICS, both were associated with a statistically significant increase in upper respiratory tract infections. Subgroups by treatment type were limited by imprecision. Observational studies suggest the possible presence of a dose-response relationship for pneumonia risk.  However, in these studies, it is difficult to rule out confounding, as more severe asthma symptoms may lead to the prescription of higher doses and, therefore, may independently increase risks from respiratory infections. The finding of increased infection risk in people using ICS is consistent with the evidence in trials of inhaled steroids used for other conditions.

There is less developed evidence that inhaled steroids may also protect against some respiratory infections

A laboratory study found formoterol and budesonide may inhibit rhinovirus infection. Another recent laboratory study found that glycopyrronium, formoterol, and a combination of glycopyrronium, formoterol, and budesonide inhibit replication of one type of coronavirus (HCoV-229E).


The evidence-base from randomized controlled trials is comparatively small and pooled estimates have wide confidence intervals. It may be that inhaled corticosteroids have different effects on different kinds of respiratory infections. We are yet to have any data on inhaled corticosteroids as they relate to COVID-19. As asthma is in itself associated with an increased risk of serious respiratory infections, observational studies analysing associations between inhaled steroids for asthma and respiratory infection may be subject to confounding.

Disclaimer:  the article has not been peer-reviewed; it should not replace individual clinical judgement and the sources cited should be checked. The views expressed in this commentary represent the views of the authors and not necessarily those of the host institution, the NHS, the NIHR, or the Department of Health and Social Care. The views are not a substitute for professional medical advice.

About the authors

Jamie Hartmann-Boyce is a Departmental Lecturer and Deputy-Director of the Evidence-Based Health Care DPhil programme within the Centre for Evidence-Based Medicine in the Nuffield Department of Primary Care Health Sciences, University of Oxford.


Richard Hobbs is a GP and Nuffield Professor of Primary Care Health Sciences, Director, NIHR English School for Primary Care Research and Director, NIHR Applied Research Collaboration (NIHR ARC) Oxford.