PROLIFIC ChemoprophylaxisTrial (COVID-19)

The number of confirmed cases of COVID-19 infectious disease arising from the SARS-CoV-2 coronavirus is rising substantially and rapidly, with the potential to overwhelm the ability of the entire National Health Service (NHS) to cope with the increased demand. The availability of personal protective equipment is limited and reports of high risk procedures such as aerosol generating procedures (e.g. intubation for the sickest patients) is a source of great concern for infection transmission. Frontline NHS staff with direct patient contact have the highest likelihood of exposure to SARS-CoV-2 and development of COVID-19 disease. Efforts to protect these workers from development of COVID-19, using drugs to prevent the disease, require urgent evaluation. This trial will be a double-blind, randomized, placebo-controlled trial in a cohort of frontline healthcare workers, who will potentially be exposed to SARS-CoV-2. Eligible participants will be frontline NHS workers aged 18 to 70 years who work in a healthcare setting with direct patient care. Participants will be randomised to one of 3 arms and receive either: (1) Hydroxychloroquine Daily (loading phase: 800mg for first 2 days; maintenance phase: 1 x 200mg tablet every day) + weekly placebo; (2) Hydroxychloroquine weekly (loading phase: 800mg for first 2 days; maintenance phase: 2 x 200mg tablets every 7th day/weekly) + daily placebo, or (3) placebo (daily and weekly). Participants will be reviewed at an interim visit 6 weeks after baseline and again and the end of the study treatment in 90 days (approximately 3 months) after randomization. Participants will also complete brief questions about their health weekly while on treatment (remotely, via app/web/phone-based interface).