Proof of whether hydroxychloroquine (HCQ), the controversial anti-malarial drug, can stave off COVID-19 infection will be available by July, a senior scientist of the Indian Council of Medical Research (ICMR), leading a large trial of the drug in healthcare workers, told The Hindu .
In the largest Indian study of its kind, 2,000 doctors, nurses, paramedical workers, lab technicians and sanitary workers at five Indian hospitals are part of this trial, which began in May.
The aim of the observational study is to check if at all, and to what extent, a regimen of HCQ will shield these healthcare workers, who work in dedicated COVID-19 hospitals — and therefore at high risk of contracting the novel coronavirus. The participants were first confirmed negative for the virus.
Ideally the efficacy of a drug ought to be measured through a double-blind randomised clinical trial. Here, one group of participants — whose identities are unknown to the doctor — will be given a dummy drug to rule out a placebo effect.
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“That’s the ideal situation,” said Suman Kanungo, Scientist, ICMR-National Institute for Cholera and Enteric Diseases, who is coordinating the study. However, the ICMR “settled” for an observational study because it would be “unethical” to deny someone the medicine if there was even a slight beneficial effect and secondly, because participants were already on the medicine the trial organisers could not find a control group, he added. “Keeping these limitations in mind, the National Task Force recommended that we go ahead with an observational trial.”
While not recommended for the public as a preventive, the ICMR’s default position, since March 21, has been to allow the use of HCQ in people at high risk of contracting the virus. These include asymptomatic healthcare workers involved in the care of suspected or confirmed COVID-19 cases and asymptomatic household contacts of laboratory confirmed cases.
Also read: Coronavirus | Hydroxychloroquine cover extended to frontline workers
On May 22, it expanded it to include asymptomatic front-line workers, such as surveillance workers deployed in containment zones and paramilitary/police personnel involved in COVID-19-related activities. There are caveats though: the drug is inadvisable in those with retinopathy, cardiac rhythm disorders and pre-existing cardiomyopathy.
Coincidentally, this was also a day when a study of 96,000 hospitalised SARS-CoV-2 patients across six continents, published in The Lancet , found no benefit — even additional harm — in those being treated with HCQ and related chloroquine.
Dr. Kanungo said he was aware of this study but it was still important to wait for observational data from India. Like the Lancet study, several others have shown HCQ not to benefit moderately sick or those severely ill with COVID-19. There are yet no studies — though several are in the pipeline internationally — that can definitely rule out if it works as a preventive in those apparently healthy.
Also read: Coronavirus | Hydroxychloroquine not effective against COVID-19, says Study
“There are mixed results from all over and the process of establishing efficacy is ongoing. At some point, we will do a meta-analysis that will examine all studies to determine the effect. In the meantime, the drug is being prescribed with adequate safeguards. Remember, this is not an antiviral. It doesn’t kill the virus, only modulates the immune system (to mount a measured response to the virus). The cardiac problems have been observed when HCQ is given in a combination with azithromycin. In our study, we are using it as a single dose drug,” he added.
In Friday’s guidelines, the ICMR cited three studies to advocate for expanding the high-risk groups that would benefit from HCQ. Among them are a retrospective case-control analysis at the ICMR that found “significant dose-response” between the number of prophylactic doses taken and the frequency of occurrence of SARS-CoV-2 infection in symptomatic healthcare workers, and a study from three Central government hospitals in New Delhi that showed those on HCQ prophylaxis were “less likely” to develop infection, compared with those who were not on it. The benefit was less pronounced in healthcare workers caring for a general patient population. An observational prospective study of 334 healthcare workers at the AIIMS, out of whom 248 took HCQ prophylaxis (median 6 weeks of follow-up) in New Delhi, also showed that those taking HCQ prophylaxis had “lower incidence” of infection than those not taking it. However, no numbers bolstering these were provided.