One of the primary purposes of corticosteroids is to suppress immune activity and inflammation: that's exactly why they are used in asthma.
Of course the immune system has an actual job besides causing nuisance inflammation: fighting infection.
For some infections, the harm to the infected person caused by the immune reaction itself is worse than that of ...
The Lancet article you referenced in your question answered the questions you asked. In the trials of high dose corticosteroids used to treat SARS patients
Corticosteroids use was:
not associated with a difference in 90-day mortality (adjusted odds ratio 0·8, 95% CI 0·5–1·1; p=0·12)
associated with delayed clearance of viral RNA from respiratory tract ...
There isn't really a scientific consensus. There appears to be a connection between cortisol and depression, but cortisol anomalies appear neither necessary nor sufficient for depression
The scientific community believed that there is a strong connection between the "happiness hormone" serotonin (5-HT or 5-hydroxytryptamine). This so-called ...