There is a row going on over a study (in Lancet) that impacted a major WHO decision but had to be retracted later, and another study (in NEJM) that undercut HCQ’s much-touted efficacy as a prophylaxis for Covid cases.
Here is a look at the chain of events that led to the latest row about the drug that has left the medical fraternity divided.
What is it all about?
Top medical journal Lancet recently retracted a study, by professor Mandeep Mehra of Harvard and the Brigham and Women’s hospital, that had raised questions about the effect of chloroquine and hydroxychloroquine, two old malaria drugs, on Covid patients.
The study, which pulled data from 96 thousand patients across four continents, said that HCQ caused higher mortality in its trial patients.
WHO’s decision to stop its Covid-19 Solidarity trial was based on the findings of professor Mehra’s study. The trial, however, was later resumed.
Why did the study spark such a row?
A significant number of clinicians from across the world immediately cast doubts on the findings. Questions were raised about the reliability/integrity of the data as well as the trial method.
The clinicians also objected that the authors failed to adhere to standard practices followed in the machine learning and statistics community. Another objection was that they did not release their code or data and quoted implausible chloroquine-to-HCQ ratios in some cases.
Questions were also raised about Surgisphere, the company that supplied the data for the trial.
What led to doubts on HCQ’s efficacy as prophylaxis?
Around the same time, another study published in the New England Medical Journal (NEJM) raised doubts about the usage of HCQ as a useful preventive measure against Covid-19.
The main contention of this study was — “high-risk contacts who were already living, or came in contact, with a Covid-19 positive patient” had no use for HCQ as (post-exposure) prophylaxis. In short, HCQ can’t prevent these groups of people from getting the disease.
In the exact words of the authors: “After high-risk or moderate-risk exposure to Covid-19, hydroxychloroquine did not prevent illness compatible with Covid-19 or confirmed infection when used as post-exposure prophylaxis within 4 days after exposure.”
So, is there no benefit of HCQ at all?
The NEJM study didn’t entirely rule out possible HCQ benefits — they said there could be “a marginal possible benefit from prophylaxis in a more at-risk group.” The authors, however, cautioned that the risks typically associated with HCQ (such as possible heart failure) very much remain, which could likely negate any potential benefit.
Besides, the research largely involved younger subjects. Risks associated with HCQ may not manifest themselves in the young, but may severely harm the older population.
What are the other key details of the study?
The randomized double blinded placebo trial recruited 821 participants, of which 719 said they were high-risk contacts as they had exposure to a confirmed Covid-19 patient.
Most participants in this trial were not tested to determine if they turned Covid-19 positive through a RT-PCR test, because of the shortage of test kits in cities like Montreal and Minnesota. So the researchers based their decision that the participants in trial got the disease through symptoms displayed.
“We acknowledge that this trial has limitations. Because of the lack of availability of diagnostic testing in the United States, the vast majority of the participants, including health care workers, were unable to access testing. Thus, an a priori symptomatic case definition was used,” the researchers wrote as their concluding remarks.
As of now, side by side with studies that deal with HCQ’s prophylactic use, there also are several Randomized Control Trials (RCTs) underway — which include on by the WHO to determine if the drug works as a treatment for Covid-19, i.e. on those patients who have already contacted the disease. The second category of studies are basically trying to find out whether or not does HCQ bring down the viral count in patients.
How do the latest developments impact India?
The NEJM study puts countries like ours in a bit of a spot. In India, as in several other countries, families of Covid-19 patients have been asked to take hydroxychloroquine as a preventive drug.
The ICMR last month extended the use of this drug as prophylaxis after it found through observational studies that the drug did not have much side effect. Besides, there have also been a few anecdotal evidence of HCQ working on high-risk groups like cops and healthcare workers who had taken it as a preventive drug.
The Lancet study also came as a jolt for several countries including India who were conducting their own HCQ trials. India, however, did not stop its trials.
Text source: Divya Rajagopal, ET Bureau
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