Here is an update to the most famous French study by Raoult on hydroxychloroquine (in combination with the antibiotic azithromycin for secondary bacterial lung infections) performed on March 6th and then March 20th:
Remember, the studies are preliminary and need more research to understand why some patients get better and some don't - quite a significant amount do not.
The three biggest problems with the current studies are:
1. The studies were small, not double-blinded and randomized - they were 80 patients with already mild forms of the disease (still ambulatory) and there appear to be two phenotypes, mild and severe forms.
2. Hydroxychloroquine has a significant risk profile for adverse events and side effects, including blindness.
3. Hydroxychloroquine is fairly expensive - it's around a $1 USD a pill.
Other small studies have been done with similar inconclusive findings, meaning there is some improvement in some patients, but not all, and that needs to be better understood before we just start handing everybody an expensive drug with a high-adverse-event risk profile out like it's candy.
*Definitions for those not familiar with clinical studies:
A "double-blind" study is one where neither the patient nor the treating physicians themselves know whether the patient is receiving the actual drug or comparator drug (in this case, we don't have a comparator).
A "randomized" study means that whether or not you receive the treatment or the placebo (or comparator drug) has been randomized, like the lottery - which also would be unethical to do in this situation.
In other words, it would take a randomized, double-blind study on a larger scale to get the answers we need, but we can't because it's unethical.
It would mean though all study participants were diagnosed with COVID-19, some participants would be given placebos instead of hydroxychloroquine, which may give false hope, actually still risking death - and we don't have an antidote yet to be able to intervene and save them if they did poorly in the clinical trial.
(Don't forget, hydroxychloroquine itself has a higher death rate associated with it versus other drugs, too.)
Therefore, IMO, the quickest best hope we actually have would be to develop a vaccine quickly - inject a tiny amount of the genetically-altered/safer form of the virus into your immune system, so your body can create antibodies to it and know how to fight the virus when presented with it - and several countries are already working round the clock on this, as we speak.
(This would likely also include a titer to check first whether your body already had created antibodies from prior exposure and/or experienced milder symptoms, but didn't know it was SARS-CoV-2, the virus that causes COVID-19.)