In a clinical trial including 4600 subjects at risk of COVID 19 infection reported that an inhalable asthma medication reduced the duration of the symptoms of COVID 19 by 3 days approximately. 

In a research conducted by Butler and Hobbs tested budesonide in people with COVID-19 symptoms treated under home settings. Patients who were on budesonide therapy twice daily reported that their COVID-19 symptoms recovered three days earlier compared with those who were not on steroid therapy. 

Resource: Yu LM, Bafadhel M, Dorward, et al. Inhaled budesonide for COVID 19 in people at higher risk of adverse outcomes in the community: interim analyses from the PRINCIPLE trial. medRxiv and bioRxiv. Accessed on 19/05/2021 from https://www.medrxiv.org/content/10.1101/2021.04.10.21254672v1#disqus_thread