Pre exposure Hydroxychloroquine Prophylaxis for COVID-19 in healthcare workers: a retrospective cohort

Background While several trials are ongoing for treatment of COVID-19, scientific research on chemoprophylaxis is still lacking even though it has potential to delay the pandemic allowing us time to complete research on vaccines. Methods We have conducted a cohort study amongst Health Care Workers (HCW) exposed to COVID-19 patients, at a tertiary care center in India where there was an abrupt cluster outbreak within on duty personnel. HCWs who had voluntarily taken hydroxychloroquine (HCQ) prior to exposure were considered one cohort while those who had not were considered to be another. All participants with a verifiable contact history were tested for COVID-19 by rtPCR. The two cohorts were comparable in terms of age, gender, comorbidities and exposure. The primary outcome was incidence rates of rtPCR positive COVID-19 infection amongst HCQ users and non users. Results 106 healthcare workers were examined in this cohort study of whom 54 were HCQ users and rest were not. The comparative analysis of incidence of infection between the two groups demonstrated that voluntary HCQ usage was associated with lesser likelihood of developing SARS-CoV-2 infection, compared to those who were not on it, X2=14.59, p<0.001. None of the HCQ users noted any serious adverse effects. Conclusions This study demonstrated that voluntary HCQ consumption as pre-exposure prophylaxis by HCWs is associated with a statistically significant reduction in risk of SARS-CoV-2. These promising findings therefore highlight the need to examine this association in greater detail among a larger sample using Randomised Controlled Trials (RCT).