Update I. A systematic review on the efficacy and safety of chloroquine/hydroxychloroquine for COVID-19.

Purpose: To assess efficacy and safety of chloroquine (CQ)/hydroxychloroquine (HCQ) for treatment or prophylaxis of COVID-19 in adult humans.

Materials And Methods: MEDLINE, PubMed, EMBASE and two pre-print repositories (bioRxiv, medRxiv) were searched from inception to 8th June 2020 for RCTs and nonrandomized studies (retrospective and prospective, including single-arm, studies) addressing the use of CQ/HCQ in any dose or combination for COVID-19.

Results: Thirty-two studies were included (6 RCTs, 26 nonrandomized, 29,192 participants). Two RCTs had high risk, two 'some concerns' and two low risk of bias (Rob2). Among nonrandomized studies with comparators, nine had high risk and five moderate risk of bias (ROBINS-I). Data synthesis was not possible. Low and moderate risk of bias studies suggest that treatment of hospitalized COVID-19 with CQ/HCQ may not reduce risk of death, compared to standard care. High dose regimens or combination with macrolides may be associated with harm. Postexposure prophylaxis may not reduce the rate of infection but the quality of the evidence is low.

Conclusions: Patients with COVID-19 should be treated with CQ/HCQ only if monitored and within the context of high quality RCTs. High quality data about efficacy/safety are urgently needed.