Researchers in the UK are to deliberately infect healthy volunteers with the virus that causes Covid-19 in the world's first human challenge trials for a potential vaccine, after the Government put $43.4m (£33.6m) towards the project. 

The trials are likely to begin in January 2021 at a quarantine facility in London, according to the Financial Times. Volunteers will be given a potential vaccine a month ahead of the trials, in which they will be given a dose of Sars-Cov-2. The goal of deliberately infecting volunteers with the disease is to significantly decrease the time it takes to figure out if the vaccine has worked, and enable scientists to figure out which vaccines hold the most promise.

"Challenge trials" have been used before to test other illnesses, including cholera, typhoid, and malaria to great effect. The world's first vaccine – for smallpox – was tested in this way, although in a way that almost certainly wouldn't get past an ethics board today. In 1796, smallpox was killing around 10 percent of the population. The common practice at the time was to infect people with small doses of the disease, as it was safer than them receiving a larger dose later on. 

Edward Jenner had heard rumors that milkmaids were immune to smallpox, and guessed (as others had) that exposure to cowpox had given them protection. Now, for the unethical bit: He decided to test this hypothesis by injecting the puss of an infected milkmaid into the 8-year-old son of his gardener, before deliberately giving him smallpox. In case you can't tell, giving deadly diseases to the kids of an employee who might feel coerced into saying yes is a bit of an ethical no-no. 

He went on to give the boy 20 more doses of smallpox, just to be sure his vaccine had worked, before carrying out further trials on poor farmworkers, their children, and workhouse inmates over the next two years. Basically, if they were vulnerable, Jenner was waiting nearby in the shadows ready to pounce with a syringe full of deadly disease.

Such ethical conundrums won't be encountered in the Covid-19 challenge trials, which will rely on young and healthy volunteers who are at much lower risk of the disease than older age groups, though that's not to say it's entirely risk-free.

Surprisingly, there are a lot of people willing to get infected for the trials. In the UK, 2,000 people have signed up through the challenge trial advocate group 1DaySooner, with over 37,000 people volunteering worldwide. The organization, led by Imperial College London and pharmaceutical and biotech company hvivo, is petitioning the UK parliament for funding for a quarantine facility big enough to house 100-200 volunteers.

"I think the challenge trial has the potential to save thousands of lives and really bring the world out of the pandemic sooner," 18-year-old British student and petition organizer of 1DaySooner, Alastair Fraser-Urquhart, told BBC News of his decision to volunteer himself for trials.

"It is just something that made instant sense to me. I'm in the lowest-risk category for Covid so why wouldn't I make that choice and help save other people who would deal with it far worse than me?"

There are of course still ethical concerns around deliberately infecting people with Covid-19, particularly as it does not yet have a very effective treatment, and the long-term effects are still being discovered. The trial will need to be approved by an independent ethics committee before it is allowed to go ahead, as well as the UK Medicines and Healthcare products Regulatory Agency (MHRA), which will balance the risks of the trials against potential benefits.

“When we are facing an unprecedented global threat from Covid, it is an ethical imperative to carry out well-controlled challenge studies to help develop a vaccine and then to identify the best vaccines,” Dominic Wilkinson, professor of medical ethics at Oxford University told the Financial Times. “The ones emerging first from clinical trials are unlikely to be the best.”

If you're interested in being involved in the trials, you can sign up here.