Is Hydroxychloroquine a Potential Treatment for COVID-19?

Disclaimer: I am not a medical professional whatsoever. My only contribution here is to assemble some links to primary sources from medical professionals, and provide what I hope is a useful and accurate summary. I hope this is of value to some, and I sincerely hope that I am not accidentally adding to the tide of misinformation out there. Be safe.

For the past 5 days or so I have been tracking a low-level rumbling that there may be a drug that has significant benefits for the treatment of COVID-19. Perhaps it was a complete coincidence, but when I woke up this morning there were three adjacent tweets in my timeline that mentioned the therapy that I have been following. So in case there is a lot of sudden interest in this topic I thought it would be helpful to pull together some links to articles written by medical professionals which are believable and relevant. It is clear that there is no “cure” for COVID-19, (possibly excepting a future vaccine) and I am definitely not suggesting that this is one. But anything which mitigates the damage by measurable percentages is going to help at scale.

Hydroxychloroquine (HCQ) and chloroquine (CQ) were originally developed over 60 years ago for the treatment and prevention of malaria. The compounds are used today primarily for the treatment of arthritis and autoimmune disorders. They are both on the WHO Model List of Essential Medicines, medications considered to be most effective and safe to meet the most important needs in a health system. They are potentially promising in the mitigation of the COVID-19 pandemic for a number of reasons.

1. They appear to help reduce the COVID-19 viral load in measurable ways.
2. They are available now.
3. They have been safely used for decades for both the treatment and prevention of malaria and other disorders.
4. The patents have long expired, so the cost per dose is low.
5. The patents have long expired, so production is not controlled by any one company and can therefore be ramped up quickly.

From the sources I show below these drugs are already listed in the COVID-19 standard treatment guides for at least three countries: China, South Korea, and Belgium.

On the negative side, as they are no longer effective for the treatment of malaria I speculate that the available quantity is currently limited, but as stated above, presumably supply could be ramped up quickly. There can also be negative side effects in large doses and when people are already seriously ill.

Note that most of the sources cited below state that it is believed that HCQ is more effective than CQ for the treatment of COVID-19. Several articles also discuss combining these drugs with others for improved outcomes. Some of those combinations are with newer antiviral drugs. In the French clinical study referenced in #1 below in cases where it was clinically indicated they combined HCQ with azithromycin, a widely used generic antibiotic. They speculate that there could be synergistic effects from the combination.

One possibility that I find particularly intriguing is that it may be possible that these compounds could (highly speculative, please see #3 and #4 below) be used as a prophylaxis for medical staff. Both HCQ and CQ were safely used for many years as a prophylaxis for the prevention of malaria. Anything that helps to keep our medical professionals healthy throughout this pandemic could dramatically improve the potential outcomes.

Below are articles that are written by medical professionals. This list is not exhaustive, but they are the most authoritative ones that I have found to date. I note with interest that with a little searching you can find that China has prioritized the manufacture of chloroquine, and the UK just banned its export. So it seems like some folks are taking it seriously. It is also mentioned as a promising therapeutic in the WHO report from their mission to China. I would add that you can also find some sensationalized reports of a “cure”, that in my humble opinion are not helpful at this point.

1. A new (March 2020) clinical trial in France demonstrates the utility of hydroxychloroquine, relative to a control group. I believe that this is deeply significant as it is a current, properly constructed clinical trial.
   
   Key quote: “We show here that hydroxychloroquine is efficient in clearing viral nasopharyngeal carriage of SARS-CoV-2 in COVID-19 patients in only three to six days, in most patients. A significant difference was observed between hydroxychloroquine-treated patients and controls starting even on day3 post-inclusion. These results are of great importance because a recent paper has shown that the mean duration of viral shedding in patients suffering from COVID-19 in China was 20 days (even 37 days for the longest duration)”

2. The Belgian COVID-19 treatment guide published March 16, 2020.
3. An article entitled “An Effective Treatment for Coronavirus (COVID-19)” from March 13, 2020 from Stanford, UAB, and researchers from the US National Academy of Science that is partially based on the published treatment guidelines established in China and South Korea. It also asserts that Chloroquine may serve as a prophylactic (preventative) measure against COVID-19.
4. A Reddit article that discusses the efficacy of using chloroquine as a COVID-19 prophylaxis for medical staff. (There is as much interesting content in the comments as in the article itself.)
5. This article from China indicates that hydroxychloroquine is more effective than chloroquine. It concludes that “…a loading dose of 400 mg twice daily of hydroxychloroquine sulfate given orally, followed by a maintenance dose of 200 mg given twice daily for 4 days is recommended for SARS-CoV-2 infection...”.
6. A letter to the editor of Nature published February 4, 2020.
7. A 2004 article on the efficacy of using chloroquine to treat the original SARS. I speculate that it may have been research such as this that motivated clinicians to try HCQ to treat COVID-19 in the first place.