COPCOV trial

Chloroquine/ hydroxychloroquine prevention of coronavirus disease (COVID-19) in the healthcare setting


We want to find out if hydroxychloroquine (HCQ) can help prevent COVID-19 infection. At the moment we don’t know.

Recruitment in the UK is now closed and we are no longer seeking further expressions of interest

What we’re asking you to do:

  • Attend a screening visit where you will:
    • answer some questions about your health and any medications you are taking
    • complete a quality of life questionnaire
    • have your height and weight measured
    • give a blood sample from a vein in your arm and two spots of blood from a finger-prick.
  • Take either hydroxychloroquine or placebo capsules for three months.
  • Record your temperature and how you feel twice a day on a smart-phone app.
  • Take a nose swab at home if you develop COVID-19 symptoms during the study.
  • Attend three check-ups (30 days, 60 days) and at the end of the study (90 days).

to do

Who can take part?

You can take part if your work involves healthcare (NHS or non-NHS). If you don’t work at one of the study sites, for example if you are ambulance staff, work in primary or a community setting or care home, please register your interest at your nearest participating site.

Where can I take part?

Register your interest at a participating site: (Recruitment in the UK has now stopped)

We are no longer adding more sites; please revisit this page if there is currently no site near you.

  • Brighton and Sussex University Hospitals NHS Trust
  • Oxford University Hospitals NHS Trust
  • Imperial College Healthcare NHS Trust
  • University Hospitals Coventry and Warwickshire NHS Trust
  • University Hospitals of Morecambe Bay NHS Trust
  • The Dudley Group NHS Foundation Trust
  • The Princess Alexandra Hospital NHS Trust
  • Birmingham and Solihull Mental Health NHS Foundation Trust
  • Greater Manchester Mental Health NHS Foundation Trust
  • Rotherham Doncaster and South Humber NHS Foundation Trust

Hydroxychloroquine and COVID-19

Two large trials found HCQ has no benefit as treatment in hospitalised patients with COVID-19. However it may help in prevention.

A trial where people were given HCQ after exposure to COVID-19 suggested there could be a protective effect but this might have been due to chance. If the effect was real then, if given before exposure, HCQ may work well enough to protect against COVID-19. This is what the COPCOV trial aims to find out.

HCQ taken in the doses and for the duration used in COPCOV has an excellent safety record. The two clinical trials mentioned above did not find any significant harms. Even so, as a precaution, COPCOV will stop the study drug in participants who do get COVID-19 and are admitted to hospital.

HCQ is easily manufactured, inexpensive and well tolerated. If effective at preventing COVID-19 this would be a huge benefit for healthcare workers and many other groups of people across the world.

Please read the full information leaflet and discuss with the study team if you would like to before deciding.

Download a PDF »