The prophylactic effect of hydroxychloroquine on the severity of COVID-19 infection in an asymptomatic population: A randomized clinical trial

Background: Laboratory and observational data suggest that hydroxychloroquine (HCQ) has biological activity against SARS-CoV-2, potentially permitting its use for disease prevention. This study aimed to evaluate the hydroxychloroquine effect as prophylaxis for SARS-CoV-2 infection. Methods: In this double-blind randomized controlled trial,  1000  healthy people without any signs and symptoms of COVID-19 were randomly assigned in a 1:1 ratio to receive either 800 mg hydroxychloroquine or placebo (four 200 mg tablets in two divided doses on day 1 of the first week, followed by 200 mg (in a single dose) weekly for the next 6 weeks). Results: Among 871 participants who remained and followed within 10 weeks 97(11.1%) became SARS-CoV-2 positive. there were statistically significant differences between infected or non-infected in the hydroxychloroquine (36 of 97 [37.1%]) and placebo (61 of 97 [62.9 %]) groups with a risk ratio of 2.1 (95% confidence interval (CI) 1.01 - 3.21; p = 0.005). The incidence of severe forms of COVID-19 ( hospitalized in the coronavirus ward or the ICU) was 2 of 97 (0.02 %) in participants who received a placebo compared to hydroxychloroquine. The proportion of non-infected people who received hydroxychloroquine prophylaxis was nearly twice higher than that of placebo users (1.87, 95% CI: 1.19 - 2.84, p = 0.05). There were no significant differences between the two groups regarding side effects (1.1% vs. 0.9%), and no severe adverse reactions were observed. Conclusion: Pre-exposure therapy with hydroxychloroquine appears to prevent moderate and severe illness caused by COVID-19 in asymptomatic persons

Effect the pre-exposure prophylactic of hydroxychloroquine on severe COVID-19 disease: a randomized controlled trial

Background. In vitro studies have shown some effects for Hydroxychloroquine (HCQ) against SARS-CoV-2 virus. Despite effective vaccination program, relatively large proportion of population remains unvaccinated. So, there still remains a need for other prophylactic measures. The present study aims to evaluate whether HCQ can prevent severe COVID-19 outcomes among health-care workers. Materials and methods. In this randomized, double blind placebo-controlled clinical trial 334 healthcare workers aged 18–65 years old were included of whom 278 individuals completed the study. Participants were randomly assigned to the HCQ group (800 mg at day one, followed by 400 mg weekly for the next 7 weeks); or the placebo group. Participants were followed three weeks after the last dose of drug or placebo (10 weeks from the first dose of drug or placebo). The primary outcome was hospitalization or death from COVID-19. Results. Of 148 people who received HCQ, none were hospitalized or died from COIVD-19, while of 130 people who received the placebo, 2 (1.5%) were hospitalized for COIVD-19 (p-value: 0.26). And, 22 (14.9%) people in the HCQ group and 15 (11.6%) people in the placebo group contracted COVID-19 (p-value: 0.99). Adverse reactions were reported by 5 (3.4%) of participants in the HCQ group and 5 (3.9%) of participants in the placebo group (p-value: 0.99). Conclusion. We found that HCQ has no significant prevention effect on the incidence of mild COVID-19. However, the low rate of hospitalization (the primary outcome) in this trial like most of the other clinical trials with HCQ would have required increasing the sample size considerably to be able to comment on the effectiveness of HCQ in prevention of severe forms including death rate. This justifies systematic reviews to include similar studies to further investigate the issue