The Medicines and Healthcare Products Regulatory Agency (MHRA) took its decision on what is known as the COPCOV trial after hydroxychloroquine was found in another British trial to have no benefit as a treatment for patients already infected with COVID-19, the disease caused by the new coronavirus.

The COPCOV study was paused pending review after the treatment trial results.

It is a randomised, placebo-controlled trial that is aiming to enrol 40,000 healthcare workers and other at-risk staff around the world, and is being led by the Oxford University’s Mahidol Oxford Tropical Medicine Research Unit (MORU) in the Thai capital, Bangkok.