My Patients Ask — What’s the Latest on Hydroxychloroquine for the Prevention of COVID?

After almost a year of incredibly contentious debate about the place of the old medication, hydroxychloroquine, in the prevention of COVID-19, we finally have what I think is the first randomized controlled trial to give us a pretty good answer — it does NOT work!

Hydroxychloroquine has been proposed as a postexposure therapy to prevent coronavirus disease 2019 (COVID-19), but definitive evidence is lacking — until now. The study, from Spain, was published in the New England Journal of Medicine last week.

The researchers, in Catalonia, Spain, randomly assigned clusters of contacts to the hydroxychloroquine group (which received the drug at a dose of 800 mg once, followed by 400 mg daily for 6 days) or to the usual-care group (which received no specific therapy).

The primary outcome was PCR-confirmed, symptomatic COVID-19 within 14 days after exposure.

The secondary outcome was COVID-19 infection, defined by symptoms compatible with COVID-19 or a positive PCR test regardless of symptoms. Adverse events were assessed for up to 28 days.

The analysis included 2314 healthy contacts of the 672 patients proven to have COVID-19 in March and April 28, 2020. Half the contacts (1116) were randomly assigned to receive hydroxychloroquine and the other half (1198) received usual care.

Results were almost identical in the hydroxychloroquine and usual-care groups with respect to the incidence of PCR-confirmed, symptomatic COVID-19 among the contacts (5.7% and 6.2%, respectively).

In other words, whether people took hydroxychloroquine on not did NOT affect whether they contracted COVID-19 or not.

In addition, hydroxychloroquine was not associated with a lower incidence of COVID-19 transmission than usual care (18.7% and 17.8%, respectively).

In other words, whether people took hydroxychloroquine on not did NOT affect whether they transmitted COVID-19 to others or not.

The incidence of adverse events was higher in the hydroxychloroquine group than in the usual-care group (56.1% vs. 5.9%), but no treatment-related serious adverse events were reported.

The bottom line is that hydroxychloroquine has risks but absolutely no benefits when taken to prevent COVID-19.

What has been proven to best prevent COIVD-19? The COVID-19 vaccines.

This blog was accurate as of the day of posting. However, as the COVID-19 pandemic rapidly evolves and the scientific community’s understanding of the novel coronavirus and the COVID vaccine develops, the information above may have changed since it was last updated. While I aim to keep all of my blogs on COVID and the COVID vaccine up to date, please visit online resources provided by the CDC, WHO, and your local public health department to stay informed on the latest news.

© Copyright WLL, INC. 2021. This blog provides a wide variety of general health information only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment from your regular physician. If you are concerned about your health, take what you learn from this blog and meet with your personal doctor to discuss your concerns.

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4 Responses to My Patients Ask — What’s the Latest on Hydroxychloroquine for the Prevention of COVID?

  1. Judy Pearson says:

    My understanding was it doesn’t prevent, but lessens worst symptoms. After I was diagnosed, I began the ZPack and hydroxychloriquine. I’d finished the 5-day ZPack, and was continuing on day 8 of the hydroxychloriquine, was feeling horrible, went to OLOL, and immediately admitted with double pneumonia. By then I was probably over the Covid…i believe it was the pneumonia that hit me hardest. My husband was on the same meds, but definitely was not affected like I was!! My initial symptoms were horrible headache, night sweats, and extreme fatigue.

  2. Hi Judy,

    Glad you’re better. Barb and I were praying for you while you were in the hospital. As to the question of hydroxychloroquine (HCQ) after one develops symptoms of COVID, there’s no evidence it’s effective and some evidence it’s harmful. The CDC not only does not recommend HCQ or HCQ with azithromycin, they actually recommend against it. Here’s their current statement:

    Chloroquine or Hydroxychloroquine With or Without Azithromycin

    1) The Panel recommends against the use of chloroquine or hydroxychloroquine with or without azithromycin for the treatment of COVID-19 in hospitalized patients.
    2) In nonhospitalized patients, the Panel recommends against the use of chloroquine or hydroxychloroquine with or without azithromycin for the treatment of COVID-19, except in a clinical trial.
    3) The Panel recommends against the use of high-dose chloroquine (600 mg twice daily for 10 days) for the treatment of COVID-19.

    A CDC website regularly updates what has been found to actually be helpful.

    Dr. Walt

  3. Marlene says:

    Hi Walt,
    I thought that Hydroxycholoroquine need to be paired with Zinc. I don’t think the study mentions anything about zinc.

  4. Marlene,

    According to the NIH, There are insufficient data to recommend either for or against the use of zinc for the treatment of COVID-19 with or without hydroxychloroquine, chloroquine, and/or azithromycin.”

    They say, “Several clinical trials are currently investigating the use of zinc supplementation alone or in combination with hydroxychloroquine for the prevention and treatment of COVID-19 (see for more information about ongoing studies).

    “The recommended dietary allowance for elemental zinc is 11 mg daily for men and 8 mg for nonpregnant women.5 The doses used in registered clinical trials for patients with COVID-19 vary between studies, with a maximum dose of zinc sulfate 220 mg (50 mg of elemental zinc) twice daily. However, there are currently insufficient data to recommend either for or against the use of zinc for the treatment of COVID-19.”

    You can read the complete recommendations here:

    Furthermore, several trials looking at zinc or hydroxychloroquine show a significant rate of side effects. The NIH adds, “Because zinc has not been shown to have a clinical benefit and may be harmful, the Panel recommends against using zinc supplementation above the recommended dietary allowance for the prevention of COVID-19, except in a clinical trial

    So, with NO evidence of effectiveness and significant evidence of side effects, I do NOT recommend this combination. At UCH health, our COVID outpatients are being treated with an FDA monoclonal antibody. Much better evidence for effectiveness and safety. You can read more about this treatment here:

    Hope this helps.

    Dr. Walt

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