Quote:

The Spanish government has announced it will be launching a clinical trial into whether hydroxychloroquine and certain antiretrovirals can prevent frontline health workers from contracting COVID-19.

The research, dubbed the Clinical Trial for the Prevention of Coronavirus Infection in Health Workers (EPICOS) will study 4,000 health workers, from wardens to doctors, at 62 hospitals in 13 regions in Spain.

The EPICOS investigation will evaluate to what extent existing medicines may offer protection against coronavirus.

One group of participants will be given the anti-malaria drug hydroxychloroquine, while another will take a combination of the antiretroviral medications emtricitabine and tenofovir, a medication currently used to treat and prevent HIV. A third group will be given a placebo.

The randomized double-blind clinical trial, which will be overseen by the Spanish Medicines Agency, will release its first results in four weeks' time.
https://www.newsweek.com/spain-study-hydroxychloroquine-antiretrovirals-covid-19-health-workers-1497277

Well, no one can say this isn't a true clinical trial as they're doing it double blind and with a placebo.
"If you will not fight for right when you can easily win without blood shed; if you will not fight when your victory is sure and not too costly; you may come to the moment when you will have to fight with all the odds against you and only a precarious chance of survival. There may even be a worse case. You may have to fight when there is no hope of victory, because it is better to perish than to live as slaves." - Sir Winston Churchill