[Garth Wilkinson (OP)]

Steroids were used without much success in SARS etc, but this is a different reaction in the lungs it seems. WHO advises against, but Brazil Japan and China have had some successes.

[chris]

The RECOVERY trial, coordinated in Oxford, are exploring this and other therapies. They are testing whether dexamethasone (a steroid) affects clinical outcome, based on the rationale you propose.

https://www.recoverytrial.net/