|LETTER TO EDITOR
|Ahead of print publication
Usefulness of hydroxychloroquine for COVID-19: Does answer lie in timing to start?
Mohan Gurjar1, Vikas Agarwal2
1 Department of Critical Care Medicine, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
2 Department of Clinical Immunology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
|Date of Submission||26-Jun-2020|
|Date of Acceptance||26-Jun-2020|
|Date of Web Publication||20-Jul-2020|
Department of Critical Care Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow - 226 014, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Two recent studies on the efficacy of hydroxychloroquine (HCQ) for COVID-19 published in The New England Journal of Medicine, one large observational study for the treatment of hospitalized patients by Geleris et al. and another randomized controlled trial (RCT) as postexposure prophylaxis by Boulware et al., did not show beneficial effect on the use of HCQ either as treatment or as postexposure prophylaxis, when compared to standard of care or placebo, respectively., The results of these studies are more provocative than definitive.
In fact, the results of RCT of HCQ for postexposure prophylaxis with the primary outcome of incidence of either laboratory confirmed or illness compatible with COVID-19 within 14 days, should be interpreted with caution, as above 80% of participants were enrolled after 24 h of exposure, including one-third on the 4th day (means one-third received drug at least after 96 h of exposure). By delaying in drug administration, severe acute respiratory syndrome-coronavirus-2 had already replicated and affected target cells in the body, if incubated.In vitro studies suggest that delaying in drug administration even by 2–5 h reduces the inhibition of virus replication., In the RCT, results might be simply affected by the timing of the drug after exposure. Almost half of the participants who developed illness had onset by the 5th day of either HCQ or placebo, while cumulative incidence of illness among placebo group showed a trend of continuous rise, higher than HCQ group, at days 10 and 14.
Considering the risk–benefit ratio and evidences fromin vitro studies, the use of HCQ could be continued as preexposure prophylaxis, especially in high-risk individuals including health-care personnel, as recommended by the Indian Council of Medical Research, till we have more evidences.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
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