What makes (hydroxy)chloroquine ineffective against COVID-19: insights from cell biology

J Mol Cell Biol. 2021 Jul 6;13(3):175-184. doi: 10.1093/jmcb/mjab016.


Since chloroquine (CQ) and hydroxychloroquine (HCQ) can inhibit the invasion and proliferation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in cultured cells, the repurposing of these antimalarial drugs was considered a promising strategy for treatment and prevention of coronavirus disease (COVID-19). However, despite promising preliminary findings, many clinical trials showed neither significant therapeutic nor prophylactic benefits of CQ and HCQ against COVID-19. Here, we aim to answer the question of why these drugs are not effective against the disease by examining the cellular working mechanisms of CQ and HCQ in prevention of SARS-CoV-2 infections.

Keywords: COVID-19; SARS-CoV-2; chloroquine; coronavirus; hydroxychloroquine.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antiviral Agents / therapeutic use
  • COVID-19 / virology
  • COVID-19 Drug Treatment*
  • Cell Proliferation / drug effects
  • Chloroquine / adverse effects
  • Chloroquine / therapeutic use*
  • Drug Repositioning
  • Humans
  • Hydroxychloroquine / adverse effects
  • Hydroxychloroquine / therapeutic use*
  • SARS-CoV-2 / drug effects
  • SARS-CoV-2 / pathogenicity


  • Antiviral Agents
  • Hydroxychloroquine
  • Chloroquine