Background

COVID-19 has caused over a million deaths. Although vaccines are being deployed, the timelines for widespread roll-out are likely to be long, particularly in areas where health systems are most fragile. Many experts anticipate that smaller outbreaks may occur in the future and that the disease is likely to stay with us for a considerable period of time. Chloroquine/ hydroxychloroquine have been in constant use for more than 60 years, are cheap, safe, well-tolerated and importantly available now, yet we still do not know, a year since the emergence of COVID-19, whether they can prevent the infection. These drugs could still be of benefit while we wait for the world’s population to be vaccinated. Chloroquine/ hydroxychloroquine could also be beneficial in future pandemics, where vaccines would not be instantly available, or if vaccines became ineffective in the current pandemic.

Front-line healthcare workers and other high-risk individuals are at increased risk of infection. It is crucial that they are protected against the disease. Adequate personal protection is key, but additional interventions could further lower the risk of infection. There are currently no drugs for the prevention of COVID-19. The World Health Organization recommends that outside the setting of a clinical trial we should not give healthcare workers any drugs claiming to prevent COVID-19 before we know that they are safe and effective.