Question & Answer

Does Chloroquine prevent or treat COVID-19?

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  • Currently, no drug has proven to be effective for preventing or treating COVID-19 (Centres for Disease Control 2020)
  • Chloroquine is a medicine that has been used for many years to treat malaria and rheumatoid conditions, such as arthritis. This drug can act against some viruses and has been used against HIV and influenza (Flu).
  • There have been suggestions in clinical circles, the media and social media that chloroquine or hydroxychloroquine, which is less toxic than chloroquine, might be useful in the prevention and treatment of COVID-19. However, there is very limited research on the use of these drugs in humans to prevent or treat COVID-19, and using these drugs has the potential to cause harmful side effects.
  • Research studies are currently underway to test and explore if chloroquine or hydroxychloroquine is safe and effective in treating COVID-19. These research studies are important, complex and take time to complete.
  • There are a number of randomised controlled trials ongoing and planned, most of which are in China. These studies will test the drugs at different doses and among people with different severity of disease.
  • The current evidence for the possibility that chloroquine might be helpful in the COVID-19 pandemic is unclear and The World Health Organization cautions against the use of unproven treatments. Further research is needed before clinicians or governments use these drugs for the prevention or treatment of COVID-19.

Things to Remember


  • Lead Researcher: Dr Colette Kelly, Health Promotion Research Centre, NUI Galway.
  • Reviewed by: Elaine Finucane, HRB-Trials Methodology Research Network, School of nursing and Midwifery, NUI Galway.
  • Evidence Advisor: Prof Andrew Murphy, General Practice, NUI Galway, Health Research Board Primary Care Clinical Trials Network Ireland
  • Evidence Advisor:  Deirdre Mac Loughlin, PPI Ignite, NUI Galway.
  • Journalist Advisor: Dr Claire O’Connell, Contributor, The Irish Times.