As per the U.S. CDC, “Chloroquine (also known as chloroquine phosphate) is an antimalarial medicine… Chloroquine is available in the United States by prescription only… Chloroquine can be prescribed for either prevention or treatment of malaria. Chloroquine can be prescribed to adults and children of all ages. It can also be safely taken by pregnant women and nursing mothers.”CDC research also shows that “chloroquine can affect virus infection in many ways, and the antiviral effect depends in part on the extent to which the virus utilizes endosomes for entry. Chloroquine has been widely used to treat human diseases, such as malaria, amoebiosis, HIV, and autoimmune diseases, without significant detrimental side effects.”The treatment guidelines of both South Korea and China against COVID-19 are generally consistent, outlining chloroquine as an effective treatment.
UPDATE: The original link went down and I replaced it with a different one. The quote no longer references the linked article.