In a study, linked here, a Brazilian institute says that hydroxychloroquine associated with azithromycin is associated with reduced hospitalization rate when given quickly to people showing symptoms of Covid-19.

How serious and trustworthy is that study?


2 Answers 2


USA Today: "COVID-19 treatment: FDA says hydroxychloroquine touted by Trump is not safe or effective", 19 May 2020:

The Food and Drug Administration is warning against the use of two drugs President Donald Trump has repeatedly touted as a possible "game changer" in the fight against the coronavirus.

The Drug Safety Communication published Friday said the agency cautions against the use of hydroxychloroquine or chloroquine for COVID-19 treatment outside of hospitals or clinical trials due to the risk of heart rhythm problems.

"Hydroxychloroquine and chloroquine have not been shown to be safe and effective for treating or preventing COVID-19," the FDA warned. Both can cause abnormal heart rhythms and a dangerously rapid heart rate, the statement said.

The FDA explicitly warned consumers not buy the drugs from online pharmacies without a prescription from a health care professional. "Consumers should not take any form of chloroquine that has not been prescribed for them by a healthcare professional," the agency stated on its website.

Business Insider: "Several new studies are raising fresh doubts on whether malaria pills should be used to treat the coronavirus, and a top US health agency just warned against widespread use", 25 Apr 2020:

A clinical trial in Brazil testing a high dose of chloroquine to treat hospitalized COVID-19 patients was halted after a spike in deaths among patients who received the drug.

The Brazilian trial, published on Friday in the Journal of the American Medical Association Network Open, added to a pile of confusing evidence around using the antimalarial pills chloroquine and hydroxychloroquine for coronavirus patients.

There's no high-quality evidence showing the medicines help patients with COVID-19, the disease caused by the coronavirus. The US Food and Drug Administration said Friday these drugs should be used only in clinical trials or at hospital because of safety risks to patients. The National Institutes of Health has advised caution in prescribing them.

New York Gov. Andrew Cuomo said Thursday night that a review of medical records by researchers at the State University of New York at Albany showed that the drug "didn't really have much of an effect on the recovery rate."

That conclusion came from a preliminary look at an observational study of about 600 people. Data from the study hasn't been published or reviewed by outside scientists, but Cuomo provided the information at a CNN town hall broadcast. Cuomo's office didn't immediately respond to requests for comment.

David Holtgrave, the dean of the Albany university's School of Public Health and lead researcher on this study, said he hoped to complete the analyses next week and would release detailed results in a peer-reviewed manner as quickly as possible.

  • 15
    "was halted after a spike in deaths among patients who received the drug." So, yeah. If you take the stuff to treat COVID19 before you go to the hospital, the hospitalization rate for COVID19 will drop - dead people don't get hospitalized.
    – JRE
    Commented Apr 25, 2020 at 13:32
  • 7
    I'll note that there have been some other more recent reports of studies finding no benefit to the therapy, but when I search for them they're lost in a bunch of noise about Lysol and ultraviolet light, for some reason. Commented Apr 25, 2020 at 13:48
  • 1
    @JRE Also, apparently that first study that had the "promising" results that caused Trump to latch on to it as a "game changer" was flawed because they didn't count the people who died from HCQ complications. I'll see if I can find a link. Commented Apr 27, 2020 at 8:24
  • 1
    I would suggest improving your answer adding the problems in the study (non.blinded, no RCT) to address the core of the question "How serious and trustworthy is that study?"
    – bradbury9
    Commented Aug 19, 2020 at 7:02

The peer-reviewed version of the Pagliaro et al. preprint mentioned by the OP is here and appears to have been published in September 2020.

This meta-analysis (Cochrane review, published February 2021) doesn't include the Pagliaro et al. study but the authors (Singh et al., lead author is from the University of Liverpool) says the following on the need for hospitalisation specifically:

Evidence for prevention of hospital admission in outpatients with COVID‐19 is very uncertain. However, given the lack of benefit in hospitalized patients, and limited available evidence suggesting little or no effect on clearance of the virus from the respiratory tract, benefit from treatment of outpatients appears unlikely.

Their more general headline conclusions are (and they refer to mechanical ventilation, so not entirely unrelated to OP's question):

HCQ for people infected with COVID‐19 has little or no effect on the risk of death and probably no effect on progression to mechanical ventilation. Adverse events are tripled compared to placebo, but very few serious adverse events were found. No further trials of hydroxychloroquine or chloroquine for treatment should be carried out.

These results make it less likely that the drug is effective in protecting people from infection, although this is not excluded entirely.

In terms of implications for research, they say:

No further trials in hospital inpatients are justified.

The evidence is less certain for ambulatory treatment of people with mild COVID‐19, and for prevention of COVID‐19 in people with, or at risk of, exposure to SARS‐CoV‐2.

Edit re. azithromycin (as per OP) Singh et al. say that "[a] higher risk of adverse events was reported in the HCQ‐and‐azithromycin arm" of the study they considered, and..

Compared with usual care in one study in 444 people, hydroxychloroquine given with azithromycin (an antibiotic) made no difference to:

· how many people died;

· how many needed mechanical ventilation; or

· time spent in hospital.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .