Human challenge trials – in which young, healthy volunteers are intentionally infected with a virus to allow vaccines and treatments to be tested quickly – have been used in the fight against diseases ranging from typhoid and cholera to malaria.
With the announcement on Tuesday of such trials to help develop a vaccine against Covid-19 there is a key difference – there are as yet very few proven therapies for the virus and we know little about its long-term effects.
But volunteers are lining up in the UK. A non-profit organisation called 1Day Sooner has attracted over 38,500 willing participants for Covid-19 challenge trials globally, including more than 2,500 in the UK. Volunteers interviewed by the Guardian say they want to participate for altruistic reasons – for the greater good, despite the uncertainty of how contracting Covid-19 could affect them.
“I would be lying if I said there’s not like an underlying worry there or fear there because this virus is less than a year old,” said Chris Holdsworth, 25, who is studying for a PhD at the University of Edinburgh.
“But at the same time I just try to contextualise the risk, without trivialising it,” he said, highlighting other procedures that pose bigger health risks to the young and fit.
The trial process is straightforward. First, an appropriate dose of the virus is selected. Then vaccinated volunteers are intentionally infected, potentially producing results quicker than conventional vaccine field trials in which researchers must wait for participants to get infected in the real world.
These studies can also be used to compare multiple vaccine candidates, develop treatments and gather data about the immediate aftermath of infection that wouldn’t be possible to procure otherwise.
In an open letter urging the UK government to support Covid-19 challenge trials last week, more than 170 scientists and academics highlighted that the mortality risk in healthy (and unhealthy) 20- to 29-year-olds was lower than donating a kidney.
Although mortality risk in the young and healthy is categorically low, other unknowns remain, such a “long Covid”, where some patients experience symptoms for months after contracting the virus.
“Even if the long-term effects turn out to be even worse than what we suspect, I still think there are many volunteers – including myself – who would be willing to go ahead because the benefit could be possibly saving people’s lives,” said 22-year-old volunteer Seán McPartlin, who is currently getting a master’s in philosophy at the University of Oxford.
McPartlin’s father is not entirely onboard with his son’s intention to partake in challenge trials, even though he appreciates the benefit of conducting such studies.
“People might think going to war is a good idea … but they don’t want the one they love to be the one who takes the risk,” he said. “It’s perfectly understandable psychologically, but indefensible intellectually, and potentially morally.”
For others, the risk of contracting the virus in the real world is reason enough to volunteer. Estefania Hidalgo Di Miele, 32, is a photography student at the University of the West of England who works the night shift at a petrol station.
“I’d rather focus on what I could be doing than fear what could happen if I get exposed to the virus,” she said, noting that, given the nature of her job, she is in any case at risk through contact with customers.
Danica Angel Marcos, 22, a 2019 graduate from the University of Lancaster, is also worried about contracting Covid-19, given the rapid hike in cases.
“There’s a chance of getting it anyway just trying to buy groceries – so I want to catch it for a reason, for a purpose,” she said.
But she wonders whether taking the risk will be worth it in the end, given the apparent rise in anti-vaccine sentiment.
“The fact that even if there is a vaccine, there are lots of people saying they wouldn’t take it – that concerns me quite a bit,” she said. “Especially when I’m wanting to do a challenge trial and wanting to risk myself in order to develop this vaccine.”