fdKen, Looks like you devoted lot of time this topic, could you please watch video, it is actually from professor who is doing very large study, and why... "COPCOV is a very large study, enrolling 40,000 participants, and will give a definite answer whether the drugs are effective and safe. COPCOV studies chloroquine and hydroxychloroquine for the prevention of COVID-19, which is different from the treatment of patients that already have the disease COVID-19, who carry a much higher load of the virus. https://www.tropmedres.ac/covid-19/copcov/copcov-key-messages