A systematic review of the prophylactic role of chloroquine and hydroxychloroquine in Coronavirus Disease‐19 (COVID‐19)

Shah, S., Das, S., Jain, A., Misra, D.P. and Negi, V.S., 2020. A systematic review of the prophylactic role of chloroquine and hydroxychloroquine in coronavirus disease‐19 (COVID‐19). International Journal of Rheumatic Diseases, 23(5), pp.613-619.

Review written by:

Anna Huang, edited by Robert Parry

Yellow - Comparative review of 5 out of 45 articles: 3 in-vitro pre-clinical studies investigating the prophylactic effectiveness of hydroxychloroquine (HCQ) and/or chloroquine (CQ) on SARS-CoV-2 and 2 clinical opinions considering the prophylactic effectiveness of HCQ and CQ on COVID-19.

Repurposing drugs such as HCQ and CQ has been promoted by some for the treatment of COVID-19. However, evidence of the effectiveness of these drugs  is scarce. A  review to determine the relevant literature through March 30, 2020, provided only 3 in vitro pre-clinical studies and 2 clinical opinions. Contradictions among in vitro studies are notable. One study demonstrates the efficacy of pretreatment with CQ and HCQ before SARS-CoV-2 exposure and reports that CQ is less effective in achieving the 50% maximal effective concentration (EC) than HCQ in cell culture modeling; a second study indicates the opposite. The third study indicates that CQ and remdesivir most successfully block virus infection among the tested drugs. One clinical opinion piece notes that the maximum daily dose for CQ is 500 mg compared to 1200 mg for HCQ, and suggests that HCQ may be less toxic than CQ. Additionally, HCQ has less tissue accumulation and is considered safe in pregnancy. Both clinical opinion pieces advocated using CQ and HCQ for prophylaxis against  COVID-19.

The review also highlights that usage of HCQ and CQ for the treatment of COVID-19 risks depleting the pharmaceutical supply for lupus and malaria patients: the population for whom the treatment is already proven successful. The availability of a chemoprophylaxis may also result in a relaxation of social distancing and hygiene protocols, which are the only proven methods to deter the virus’ spread, and thus increase the rate of transmission as well. Finally, the report calls for further clinical trials.

Review Notes
  • A lack of data in the primary literature regarding CQ and HCQ for this review.

  • The data regarding CQ and HCQ is evolving rapidly; this review considers data through March 30, 2020.

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