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An old malaria medicine, hydroxychloroquine, has gone viral on the internet. But is it really an antiviral drug?

The medicine has been seen as a potential treatment for Covid-19, the disease caused by the novel coronavirus SARS-CoV-2, almost since outbreaks started. This week it made headlines, due in part to tweets from President Trump and in part because of a small French study of 42 patients that seemed to show that hydroxychloroquine, particularly when combined with the antibiotic azithromycin, helped decrease patients’ levels of coronavirus. Unfortunately, the rumors about the drug’s efficacy have also encouraged some to buy and even consume a similarly named fish tank cleaner; one person has died.


But a second study emerged last week from Shanghai University in China of 30 patients hospitalized for Covid-19. Whether patients received hydroxychloroquine or not, their body temperature returned to normal a day after hospitalization, and the time it took for levels of the virus to become undetectable was comparable. Unlike the study from France, the patients in this study were randomly assigned to either hydroxychloroquine or the control group, which makes the results more reliable.

Jun Chen, one of the authors of the Shanghai study, called the French study’s results “interesting” but said they needed to be evaluated in another randomized study.

“Both our study and theirs had many limitations,” Chen wrote. “But personally, I would say that hydroxychloroquine was not a ‘magic’ drug, if there is any antiviral effect. And in fact, hydroxychloroquine has never been effective in any viral diseases, despite its in vitro antiviral activity.” “In vitro antiviral activity” means that the drug stops the virus from infecting cells in the dish.


The first mention of the Shanghai study came from a paper in The Lancet Global Health, where the results were described as positive. One of the authors of the Lancet paper, Oriol Mitjà, wrote via email that changes on CT scans showed “that the drug has some efficacy” against Covid-19. In the Shanghai study, worsening of the disease that could be picked up on a CT scan happened in 33% of those on hydroxychloroquine (that’s 5 patients) versus 47% of those in the control group (7 patients).

Mitjà was even more optimistic about the French study, saying it has “new and stronger data.”

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But objections have been raised to the French study  paper, even as it’s bounced around the Internet. Fox host Sean Hannity even shared another doctor’s letter on his experience using the hydroxychloroquine/azithromycin combination on his television show on March 23.

Three statisticians published a review of the French study that argued that the way it was designed made the treatments look better than they actually are. They pointed to the lack of randomization, as well as an inappropriate control group composed partly of people who refused to take the drug. They also noted that the study dropped some patients from the analysis — the small study of 42 patients actually only included data from 36. The Shanghai study, which showed less impact from the treatments, adds to the questions about the French study, wrote Tim Morris, a statistician at the MRC clinical trials unit at University College, London.

“The [French] study gave very little useful information about whether hydroxychloroquine might help,” Morris wrote. “The Shanghai study is better (because they had a meaningful control group) but gives us very little information that hydroxychloroquine doesn’t help.” The data, he wrote, are “compatible with a wide range of possible effects,” which is statistician-speak for, “Nobody knows whether the drug helps or not.”

The Shanghai study, Morris wrote, is a step in the right direction toward some bigger, better trials that are kicking off. The first of these might give some answers in April — a short time when it comes to clinical trials, but potentially after the United States, and particularly New York City, will have seen a tsunami of Covid-19 cases.

Some doctors on the front lines will use these drug combinations, particularly with patients who are so sick they are on ventilators. As one doctor told me, the risks associated with these drugs, like heart rhythm disturbance or worsening psoriasis, don’t warrant not using them in patients who are in serious trouble. But there is also a need to conduct studies of them to find out if they are truly effective. New York Governor Andrew Cuomo signed an executive order saying that pharmacists should not dispense the drugs to treat Covid-19 unless they are part of a clinical trial. Studies for another drug, remdesivir from Gilead Sciences, are expected to read out in the coming weeks.

Zach Weinberg, one of the co-founders of Flatiron Health, a division of Roche, remembers the difficult transition of going from working in online advertising, where his first company was focused, to Flatiron, which is focused on cancer. In software, more data is better. In cancer, the wrong type of data can lead to conclusions that are not only incorrect but dangerous.

“Sometimes people confuse saying, ‘the study doesn’t tell you anything’ with saying the drug doesn’t work,” Weinberg said. “That’s a really important distinction. They’re not the same thing. I’m not saying the drug doesn’t work or does work. What I’m actually saying is nobody knows if the drug works or doesn’t work.”

His lesson: when dealing with a pandemic, listen to experts who are used to grappling with these problems.

“Society tends to put people who’ve been successful in one area on a pedestal, and draw the conclusion that means they’re expert at many things even though the expertise that they had in one area has nothing to do with the other,” Weinberg said.

  • What exactly is the political aim of hyping an untested therapy – when practical solutions like physical barriers for health providers are sorely lacking? These workers are a more important asset than an unrealized miracle cure

  • Under acute cases, I have no idea why you wouldn’t use it (under physician’s supervision). Off label scrips are common and the drug combination has shown some promising results. If the patient us under sever respiratory distress in may be put on a ventilator, try it. Let me see – the choice is a) potential death vs b) trying something not yet singed off on by the FDA for this use? I’ll take b). I also find the concept of denying the treatment by the left soley based on Trump’s positive comments of it disturbing. Lives could be saved here and they want to stick their heads in the sand.

  • We do know. It has been researched over and over again ever since the military accidentally discovered it in North Afrika during WW2.
    It works, and is needed, for Lupus.
    The crime chief in the White House has been taken it away from the Lupus sufferer, by his carnival barking, and he has killed people who relied on his barking and used it.

    • “Rainer” feels the need to come here and clutter an otherwise useful dialogue with his political bias. No one is dying from what the President has said, not so sure I can say the same about how certain media outlets twist what he says with impunity. He merely stated it shows promise but may or may not work, regardless, his comments have accelerated the trials necessary to know for sure and speed saves lives.

  • I’ve been following the case of Spanish doctor Yale Tung Chen on Twitter. He was infected at work, and became very ill, indeed. He took HCQ, and then HCQ +Azith. He’s 20 days post diagnosis and is just now recovering. Did the drugs help? Perhaps, but they certainly weren’t a quick cure.

    BTW: he’s an ultrasound specialist, and shows pretty convincingly that it’s a superior imaging method for Covid.

  • I’ve been reading about the meds they are trying for coronavirus
    I must say i stand by the med Azithromycin. I have addison disease and was coughing and score throat and a week later im so much better after my dr put me on it…

  • With disease like COVID19, where 80% recovers without any intervention, it is difficult to conclude that the treatment worked. Only a well designed randomized trial can provide an answer. Both trial of HCQ/CQ were small number, one had no control arm at all, the recent one did not show any difference.

  • The important point to keep in mind that any drug that works via blood stream will not be effective in COVID19 as viremia (virus in the blood stream) is rare and only toward the end of the disease. So stop using these drugs which can potentially be more harmful than beneficial. Remember the Diamond Princess Cruise population, only 7 people died of all the about 700 infected patients, way less mortality than what see across the glob. I don’t know if any of them got chloroquine/zithormax or any other drugs.

    • Actually the pharmo kinetics of HCQ are well established in the professional literature, with studies going back as far was 20 years or more. Many articles on PubMed in this regard with linkout to full text articles on the studies. The distribution of HCQ is almost entirely in the tissues, not in the blood, and is the reason why the half life is so very long (20 to 40 days). It is particularly concentrated in tissues with melanin, which is why retiniopathy and MACD is a big issue for long term use. It is also seen in high concentration in Vero cells however, so that is the reason it can be effective against Covid19.

  • The specific language is as follows:

    The directive contained in Executive Order 202.10 related to restrictions on dispensing hydroxychloroquine or chloroquine for prophylactic purposes is amended as follows: No pharmacist shall dispense hydroxychloroquine or chloroquine except when written:

    as prescribed for an FDA-approved indication;

    for an indication supported by one or more citations included or approved for inclusion in the compendia specified in 42 U.S.C. 1396r–8(g)(1)(B)(i);

    for patients in inpatient settings and acute settings;

    for residents in a subacute part of a skilled nursing facility;

    or as part of an study approved by an Institutional Review Board.

      Any person authorized to prescribe such medications shall denote on the prescription the condition for which the prescription has been issued.

    Note: This is not legal advice and no attorney client relationship has been established by sharing this. Consult with an appropriate legal consultant before acting on this information or any other information provided by Lawyer Bob on this web site.

  • *****NY Executive Order 202.11 (March 27, 2020) New York now allows hydroxychloroquine for patients in acute, hospital or skilled nursing care.********

    As noted in the article on March 23, 2020, NY Executive Order (NYEO) 202.10 was issued by Gov. Cuomo and prohibited pharmacists from dispensing hydroxychloroquine unless approved by the FDA or for those involved in a NYS Study. However, that’s not the law of the State of New York this morning.

    Late last night NYEO 202.11 became the law of the State of NY and allows dispensation of hydroxychloroquine in “acute settings” AND in hospital settings AND in skilled nursing facilities.

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