COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

Primary Prevention Shah S, Das S, Jain A, et al. A systematic review of the prophylactic role of chloroquine and hydroxychloroquine in coronavirus disease-19 (COVID-19). Int J Rheum Dis. 2020 May;23(5):613-619. doi: 10.1111/1756-185X.13842. Epub 2020 Apr 27.

OBJECTIVE: The pandemic coronavirus disease-19 (COVID-19) has pushed the global healthcare system to a crisis and amounted to a huge economic burden. Different drugs for prophylaxis against COVID-19 including chloroquine (CQ) or hydroxychloroquine (HCQ) have been tried. This study was performed to systematically review the role of CQ and HCQ in preventing the spread of COVID-19.

METHODS: PubMed, EMBASE,, International Clinical Trials Registry Platform and Cochrane Library databases were searched for studies that evaluated the prophylactic role of CQ or HCQ on SARS-CoV-2 (pre-clinical studies) or COVID-19 (clinical studies) until 30 March 2020. The available literature was critically appraised.

RESULTS: A total of 45 articles were screened and 5 (3 in vitro pre-clinical studies and 2 clinical opinions) were included. The pre-clinical studies showed the prophylactic effects of CQ and HCQ against SARS-CoV-2. On the other hand, the clinical opinions advocated the prophylactic use of CQ and HCQ against COVID-19. However, no original clinical studies on the prophylactic role of CQ or HCQ on COVID-19 were available.

CONCLUSION: Although pre-clinical results are promising, to date there is a dearth of evidence to support the efficacy of CQ or HCQ in preventing COVID-19. Considering potential safety issues and the likelihood of imparting a false sense of security, prophylaxis with CQ or HCQ against COVID-19 needs to be thoroughly evaluated in observational studies or high-quality randomized controlled studies.

Discipline / Specialty Area Score
Pediatrics (General)
Public Health
Family Medicine (FM)/General Practice (GP)
General Internal Medicine-Primary Care(US)
Hospital Doctor/Hospitalists
Internal Medicine
Infectious Disease
Comments from MORE raters

Family Medicine (FM)/General Practice (GP) rater

THis is an interesting review that doesn't shed much light...

General Internal Medicine-Primary Care(US) rater

This article outlines the sparse data for chloroquine and hydroxychloroquine use for COVID-19. Certainly, this information is extremely timely but there is not much of it here, and I think most physicians (and knowledgeable lay people, for that matter) already understand we need much more information about these drugs before they are used generally.

Internal Medicine rater

This meta-analysis shows how easily a promising drug can be accepted and prescribed, despite no serious clinical evidence (a classical halo effect!).