The Indian Council of Medical Research (ICMR) in a new study has underlined the importance of the use of Hydroxychloroquine for prophylaxis, or disease prevention, among health care workers, saying that the consumption of four or more maintenance doses of the anti-malarial drug was associated with a significant decline in coronavirus infection among frontline workers.
The study also says a dose-response relationship existed between the frequency of exposure to HCQ. The findings, published in the Indian Journal of Medical Research, say that the study was carried out to identify the factors associated with SARS-CoV-2 infection among the healthcare workers in the country, given the elevated risk for them.
The ICMR study further acknowledges and explains the disparity in its findings with that of with a study published in Lancet , which highlighted that HCQ did not offer therapeutic benefits to severe COVID-19 cases and was associated with increased mortality.
The Lancet study of nearly 100,000 coronavirus patients had shown no benefit in treating them with anti-viral drugs hydroxychloroquine and chloroquine and even increased the likelihood of them dying in hospital.
"This apparent disparity with the findings of the current investigation could be explained by the two different application contexts. While the observational study involving registry-analysis focussed on the treatment of hospitalised COVID-19 patients, our emphasis was on the prevention of infections among healthcare workers. In treatment settings, severe COVID-19 patients are likely to have a very high viral load and cytokine levels, which may not be improved by HCQ therapy," the study said.
"Biologically, it appears plausible that HCQ prophylaxis may inhibit the virus from gaining a foothold," the study said. In the absence of clinical trial results on safety and efficacy of HCQ chemoprophylaxis in healthcare workers, this study offers evidence of public health importance.
Interestingly, the IndianJMedRes says that while this phenomenon “cannot be fully explained by the data collected through the present study, lessons from other areas of public health could be of some help”. The parallels include seat-belt legislations vis-à-vis speeding and road traffic casualties, and promotion of use of condom with unintended effects linked to greater sexual activities, it says.
In the context of the study, the ICMR says that HCQ prophylaxis is with regards to getting infected with SARS-CoV-2 as the perceived hazard, and not adhering to conventional respiratory infection prevention measures, such as PPE use, personal hygiene and social distancing as risk-taking behaviours.
The study highlights the potential antiviral and anti-inflammatory properties of HCQ with respect to its low cost of therapy and excellent oral bio-availability high tissue concentrations in the lungs relative to the plasma levels and acceptable safety profile.
The advantage of PPE usage was also independently indicated by the multivariate model, the study says. Respondents who reported never using PPEs were also at a higher risk.