A trial involving anti malarial drugs hydroxychloroquine or a placebo has begun with participants in Brighton and Oxford.
All of the participants are staff who will come into contact with a patient with Covid-19.
The trial will take place to see if the drug is effective in the prevention of contracting coronavirus.
The Brighton and Sussex University Hospitals and the John Radcliffe Hospital in Oxford will host the pilot.
Overall 25 sites have been assigned for the trial.
Results from the experiment are expected by the end of this year.
The trialing of anti malarial drugs is a global effort.
More than 40,000 healthcare workers from Europe, Africa, Asia and South America are expected to take part.
It is anticipated that in Asia contributors to the trial will be given chloroquine or a placebo.
One of the leaders of the study Prof Nicholas White at the University of Oxford is unsure if the drugs are beneficial.
They could even cause harm against Covid-19.
Yet a random but also controlled trial was the best way to find out.
What is known is that the drugs are a prevention and a treatment for malaria.
And that they can reduce fever an inflammation on an infection.
Trump a User of Hydroxychloroquine
United States President Donald Trump has openly admitted that he is taking hydroxychloroquine.
He is using the drug to fend off the threat of coronavirus.
Even though so far it is unproven, and may come with harmful side effects such as causing heart rhythm problems.
The US Food and Drug Administration has warned of its use outside of hospital.