Question & Answer

Does hydroxychloroquine or chloroquine prevent or treat COVID-19?

Click image to download
  • Chloroquine and hydroxychloroquine (which is less toxic than chloroquine) are medicines that have been used for many years to treat malaria and rheumatoid conditions, such as arthritis
  • At the start of the COVID-19 pandemic, there had been suggestions in medical circles, the media and social media that chloroquine or hydroxychloroquine might be useful to help prevent and treat COVID-19
  • A large amount of research has been carried out to investigate these suggestions
  • Randomised controlled trials have found no evidence that hydroxychloroquine or chloroquine can prevent COVID-19
  • Randomised controlled trials have found no evidence of benefit from treating people with mild, moderate or severe COVID-19 with hydroxychloroquine or chloroquine
  • The evidence does suggest that the treatment of COVID-19 with hydroxychloroquine or chloroquine could cause adverse events in people taking these medicines
  • Based on the existing evidence, the World Heath Organization recommends against the use of chloroquine or hydroxychloroquine for the treatment of COVID-19

Things to Remember


  • Lead Researcher: Dr Claire Beecher, HRB-Trials Methodology Research Network & Evidence Synthesis Ireland, University of Galway
  • Reviewed by: Professor Declan Devane, School of Nursing and Midwifery, HRB-Trials Methodology Research Network, Evidence Synthesis Ireland & Cochrane Ireland, University of Galway.
  • Topic Advisor: Dr Frank Moriarty, Senior Lecturer in Pharmacy at the School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland and visiting research fellow at The Irish Longitudinal Study on Ageing (TILDA).
  • Patient and Public Partner: Deirdre Mac Loughlin, PPI Ignite, University of Galway.
  • Journalist Advisor: Dr Claire O’Connell, Contributor, The Irish Times.

Conflict of Interest Statement: The authors have no financial or other conflicts of interest for this health claim summary.