The study received ethics approval this week, the country's Department for Business, Energy and Industrial Strategy (BEIS) said Wednesday in a statement.

During the trial, up to 90 volunteers aged 18-30 years will be exposed to Covid-19 in a safe and controlled environment to increase understanding of how the virus affects people, the ministerial department said, adding that the study will play a "key role in developing effective Covid-19 vaccines and treatments."

In regular vaccine trials, volunteers are given an experimental vaccine and then released to live their everyday lives; researchers assume that a certain percentage of them will be exposed to the virus naturally.

In a challenge trial, by contrast, participants are deliberately dosed with the virus being targeted.

Challenge trials are nothing new, and have been carried out for cholera, typhoid, malaria, and even influenza.

Proponents of the trials say that they are more efficient, requiring far fewer volunteers because researchers know for certain that everyone will be exposed to the virus, and that they can deliver scientific data more quickly.

But critics worry about exposing people to a virus for which there is no fail-safe treatment, and say that the young, healthy volunteers are not representative of the wider population.

BEIS said the version of the virus used would be the one in circulation since March 2020 -- rather than any new strains -- emphasizing that it "has been shown to be of low risk in young healthy adults."

They added that researchers will also be working very closely with the Royal Free Hospital and the North Central London Adult Critical Care Network in the UK to ensure the study will not impact on the ability of the National Health Service to care for patients during the pandemic.

After the initial trial, vaccine candidates which had been proved safe in clinical trials could be given to small numbers of volunteers, the department said, to help identify the most effective vaccines.

"Not only can human infection studies speed up vaccine development, but data from this study will provide key insights into how Covid-19 affects us from as soon as we are infected, which will potentially inform research into new treatments," said Dr. Charlie Weller, head of vaccines at UK-based global charitable foundation Wellcome.

"Together, effective treatments, vaccines and testing will help communities around the world to protect themselves and bring this pandemic to an end sooner," he told the UK's Science Media Centre.

Earlier this week the UK met its target of offering a first dose of vaccine to 15 million people by mid-February. But the country has been hard hit by Covid-19, with more than 4 million total cases recorded so far.