There is a large-scale clinical trial with 3000 participants (https://clinicaltrials.gov/ct2/show/NCT04308668 https://clinicaltrials.gov/ct2/show/NCT04308668) t

There is a large-scale clinical trial with 3000 participants (https://clinicaltrials.gov/ct2/show/NCT04308668 https://clinicaltrials.gov/ct2/show/NCT04308668) to see if chloroquine prevents progression to severe disease when given shortly after exposure, because when patients are symptomatic it was proved to be completely useless. There isn't a shortage of participants, and at that scale we'll know soon enough if Trump's wonder drug does something. Probably it won't.