N. Engl. J. Med. https://doi.org/10.1056/NEJMoa2021436 (2020)

Due to the urgency of the COVID-19 crisis, the testing of pharmaceuticals that had already cleared safety and production hurdles began within the first month of the outbreak.

Observational and compassionate-use studies of repurposed drugs proliferated rapidly, as did clinical trials. The corticosteroid dexamethasone was shown, in the large-scale UK RECOVERY trial, to reduce 28-day mortality by as much as a third in patients hospitalized with COVID-19 and receiving either mechanical ventilation or oxygen alone, compared with the mortality of those receiving the usual care.