It has the advantage of being fairly common, safe, and cheap.
According to very recent research sources quoted by Wikipedia
Hydroxychloroquine and chloroquine have been recommended by Chinese and South Korean health authorities for the treatment COVID-19.[11] [12] In vitro studies have demonstrated that hydroxychloroquine is more potent than chloroquine against SARS-CoV-2 with a more tolerable safety profile.[13]On 16 March 2020, advisor to the French Government on COVID-19, Professor Didier Raoult, announced that a trial involving 24 patients from the south east of France supported the claim that hydroxychloroquine was an effective treatment for COVID-19.[14] [15]
An amount of 600 mg of hydroxychloroquine (brand name Plaquenil) was administered to these patients every day for 10 days. The drug appeared to be responsible for a "rapid and effective speeding up of their healing process, and a sharp decrease in the amount of time they remained contagious".[16]
On March 17 after testing in several hospitals around Italy the Italian Pharmaceutical Agency has included hydroxychloroquine in the list of drugs with positive preliminary results for treatment of coronavirus disease 2019.[17]
Thank you! Fingers crossed, I’m hoping this is starting to simmer a bit.