The Indian Council of Medical Research (ICMR), the apex government body for biomedical research, which has expanded the use of hydroxychloroquine (HCQ) as prophylactic to all frontline COVID-19 workers to prevent them from contracting infection, may not budge despite criticism from several quarters.
The government said its decision to expand HCQ use is based on a retrospective case-control study at ICMR that found a significant dose-response relationship between the number of prophylactic doses taken and frequency of occurrence of SARSCoV-2 infection in symptomatic healthcare workers who were tested positive. It cited another observational prospective study of 334 healthcare workers at AIIMS, out of which 248 took HCQ prophylaxis (median 6 weeks of follow-up) in New Delhi, which also showed a lower incidence of SARS-CoV-2 infection than those not taking it. However, ICMR hasn't made public the full data related to the studies it cited.
To be sure, HCQ as treatment and as a prophylaxis are two different use cases and should, therefore, be evaluated separately.
But critics point out that ICMR could have been more transparent by providing full data of its observational studies, which were the basis of its decision. They also raise concerns over the potential side-effects of the drug, when it is given to hundreds of thousands of COVID-19 frontline workers. They also say that a randomised control trial would have been more credible to allay the fears.
So far, there wasn't any randomised control trial to test the effectiveness of HCQ as prophylactic.
Meanwhile, doctors from All India Institute of Medical Sciences (AIIMS) have defended the use of HCQ through a correspondence in the Lancet journal saying that the safety of hydroxychloroquine is well established with prolonged use. They argued that the pharmacokinetics of hydroxychloroquine, such as its long half-life and high lung concentration (500-times the blood concentration), are ideally suited for use as an agent for prophylaxis.
The AIIMS doctors were responding to the correspondence on April 17 by four Indian doctors from Mahatma Gandhi Institute of Medical Sciences, Sevagram Department of Pulmonary Medicine, Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, who raised concern over use HCQ as prophylaxis for COVID-19 in India citing scarcity of evidence, among other things.
The AIIMS doctors further said the use of HCQ as prophylaxis in selected groups of high-risk contacts is a prudent approach considering the risk-benefit analysis. They added that the drug would only be used among a targeted group which is at high risk rather than the general population.
"A paucity of data is expected in the first wave of a pandemic caused by a novel virus. HCQ has been shown to have in-vitro activity against the virus. Recently published human trials, along with other unpublished data suggest that it could decrease the duration of viral shedding and symptoms if given early. A study from South Korea shows the efficacy of hydroxychloroquine for post-exposure prophylaxis," the doctors said.
However, there is mounting evidence that HCQ has little benefit as a therapy against COVID-19; in fact it is also associated with elevated risk for the cardiac adverse effects.
Data on over 100,000 patients among three studies published in NEJM, the Lancet and JAMA have all pointed to no benefit of HCQ. The World Health Organisation (WHO) has temporarily paused the hydroxychloroquine arm within the Solidarity Trial while the data is reviewed by the Data Safety Monitoring Board.
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