South Korea has been using HydroxyChloroquine since February in their treatment protocols m.koreabiomed.com/news/articleView.html?idxno=7428
China has had a HydroxyChloroquine protocol since at least February web.archive.org/32075365-expert-consensus-on-chloroquine-phosphate-for-the-treatment-of-novel-coronavirus-pneumonia/
How it works:
We have known since 2005 that Chloroquine is a potent inhibitor of SARS coronavirus infection and spread www.ncbi.nlm.nih.gov/pmc/articles/PMC1232869/?utm_source=share&utm_medium=ios_app
Chloroquine works by opening up the pathway to allow in more Zinc.
Zinc Inhibits Coronavirus and Arterivirus RNA Polymerase Activity In Vitro and Zinc Ionophores Block the Replication of These Viruses in Cell Culture journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1001176
Chloroquine Is a Zinc Ionophore. journals.plos.org/plosone/article?id=10.1371/journal.pone.0109180