In a few short months the SARS-CoV-2 coronavirus has spread throughout the world. The virus can infect the respiratory (breathing) system, causing fever and a continuous cough, and can develop into pneumonia. There is currently no vaccine against the virus or approved specific treatment for COVID-19 (the disease caused by the virus), although remdesivir has been authorized for emergency use by the US FDA pending formal approval. Clinical trials are urgently needed to determine the effectiveness of treatments and vaccines for COVID-19. In our blog for Clinical Trials Day 2020 we look at a selection of the ongoing COVID-19-related trials that have been registered at the ISRCTN registry so far this year. Drugs The World Health Organization (WHO) has organized the international SOLIDARITY trial to compare untested treatments for COVID-19 with each other. The study treatments include drugs that are currently used to treat other conditions such as the antivirals remdesivir and lopinavir plus ritonavir, the antimalarials chloroquine and hydroxychloroquine, and interferon-beta, which is used to treat multiple sclerosis. In the UK the RECOVERY trial is assessing a similar selection of possible treatments at many hospitals. At the time of writing RECOVERY is the world’s biggest trial of drugs to treat COVID-19 patients. Like SOLIDARITY, RECOVERY has an adaptive trial design, which means that new treatments are being added to the trial as evidence emerges. Currently the treatments being tested include lopinavir plus ritonavir and hydroxychloroquine as mentioned above, as well as corticosteroids (typically used to reduce inflammation), azithromycin (a commonly used antibiotic), and tocilizumab (a treatment for rheumatoid arthritis). Hydroxychloroquine is also being tested separately in the PRINCIPLE study at GP practices in England. This study is specifically recruiting people who are at a higher risk from infection with the virus, such as people aged 65 and over, or those known to have one of the following conditions: a weakened immune system, heart disease, asthma or lung disease, diabetes, mild hepatic impairment, or stroke.