Could inhaled corticosteroids be the game changers in the prevention of severe COVID-19? A review of current evidence

As the coronavirus 2019 disease (COVID-19) pandemic is going through its second year, the world is counting more than 4.9 million lives lost. Many repurposed immunomodulatory drugs have been tried and failed to treat COVID-19. The only successful treatments that improve survival are systemic corticosteroids and tocilizumab, by targeting the systemic inflammatory cascade. An intriguing observation that patients with chronic respiratory disease seem to be less prone to COVID-19 gave ground to the hypothesis that inhaled corticosteroids (ICS) may protect them from SARS-CoV-2 infection. In this review, we summarize current evidence regarding the therapeutic role of inhaled and systemic corticosteroids in COVID-19, and we present experimental data on the potential actions of ICS against SARS-CoV-2 infection. We also discuss safety issues as well as therapeutic considerations and clinical implications of the use of ICS in COVID-19. Four randomized controlled trials (RCT) with more than 3,000 participants suggest that ICS may lead to earlier clinical improvement and lower rate of hospitalization in patients with mild COVID-19, while 9 ongoing RCTs are anticipated to provide more evidence for the use of ICS in COVID-19. Recent evidence has shown promise that ICS could provide tangible benefits to patients suffering from COVID-19.