Scientists launch trial to deliberately infect people with coronavirus after they already caught it
Scientists launch trial to deliberately re-infect coronavirus survivors – and volunteers could get paid £5,000 for taking part
- University of Oxford trial to test what level of immune prevents re-infection
- This will involve exposing people who have had Covid-19 to the virus once again
- Results could allow for vaccines that produce the golden level of immunity
Scientists have launched a trial to deliberately infect people with coronavirus after they have already had it.
The study will help establish the level of immune protection which stops people being reinfected, which could help to fast-track future vaccines.
The trial, which is led by the University of Oxford, will expose every volunteer to the virus, so that only those with a strong enough immune response will avoid being reinfected.
Researchers will hope to ascertain what level of immune response protects people.
That could mean vaccines which produce that golden level of immunity could be fast-tracked and licensed without trials of tens of thousands of people being necessary.
Scientists have launched a trial to deliberately infect people with coronavirus after they have already had it. The study will help establish the level of immune protection which stops people being reinfected, which could help to fast-track future vaccines (stock image)
Study lead and Professor of vaccinology, Helen McShane said: ‘If we can determine… that a certain level of antibodies means it’s not possible to reinfect somebody, that would feed very immediately into designing the most effective vaccines.’
The study, which is funded by the Wellcome Trust and is expected to start this month after receiving ethics approval, will recruit people aged 18-30 who have previously been naturally infected with Covid.
They will be re-exposed to the virus in a safe and controlled environment while a team of researchers monitor their health.
Volunteers will receive up to £5,000 for taking part in the study.
They will have to be quarantined for at least 17 days after getting infected, and will be followed-up over the course of a year.
Human challenge studies have played a key role in furthering the development of treatments for diseases such as malaria, TB, typhoid, cholera and flu.
A similar study is ongoing in the UK where volunteers are being infected with Covid to test vaccines and treatments.
Healthy volunteers are paid £4,500 to get infected with the virus, with scientists keeping them under 24-hour surveillance until they recover.
Participants are administered with a tiny dose of Covid via a nasal spray, and then asked to lie flat on their backs for 30 minutes to allow it to seep into their respiratory system.
They are then quarantined at the Royal Free Hospital, London, for about two weeks or until they recover from the infection. They then have follow-up appointments every few weeks for a year.
The first volunteers were infected in early March, and have now been discharged following no ill-effects.
While Covid infections have been rare, recent research suggests prior infection may not fully protect young people against reinfection.
The observational study, published in the Lancet involving US Marine Corps members mostly aged 18-20, showed that between May and November 2020, around 10 per cent of participants who had previously caught Covid became re-infected.
The Oxford study will take phase in two phases.
The first phase, involving 64 healthy volunteers, will aim to establish the lowest dose of virus which can take hold and start replicating.
Once the dosing amount is established, it will be used to infect participants in the second phase of the study, which is expected to start in the summer.
Professor McShane said: ‘We will measure the immune response at several time points after infection so we can understand what immune response is generated by the virus.
‘A challenge study allows us to make these measurements very precisely because we know exactly when someone is infected.
‘The information from this work will allow us to design better vaccines and treatments, and also to understand if people are protected after having Covid, and for how long.’
The trial, which is led by the University of Oxford, will expose every volunteer to the virus, so that only those with a strong enough immune response will avoid being reinfected. Researchers will hope to ascertain what level of immune response protects people (stock image)
The participants will be quarantined for 17 days under and cared for by the research team at a hospital until they are no longer at risk of infecting others.
Those who develop symptoms will be given a monoclonal antibody treatment developed by Regeneron, which contains laboratory-made antibodies that have shown to reduced the risk of disease progression in clinical trials.
The full length of the study will be 12 months, which will include eight follow-up appointments after discharge.
Professor McShane said those taking part will be reimbursed for their efforts, which will be just under £5,000 for each participant.
How scientist Edward Jenner used eight-year-old son of his gardener for the first ever challenge trial
Edward Jenner pictured in a portrait
Esteemed scientist Edward Jenner used the eight-year-old son of his gardener for the first ever challenge trial, with just a hunch as to whether it would be successful.
Luckily, it worked. And the study led to the invention of the smallpox vaccine, which saw the debilitating disease eradicated in 1977, more than a hundred years later.
The life-threatening condition caused fever, vomiting, mouth sores and fluid-filled blisters to appear on the skin which would then develop scabs.
Victims would be left with life-long scarring on their skin, and 30 per cent of all those who suffered from the disease would eventually die.
But, after the vaccine was administered worldwide, deaths from smallpox plunged from 150million in the 1950s to zero today.
How did the first challenge trial come about?
Edward Jenner had the idea for the trial after hearing about an old country tale, which said milkmaids who caught cowpox from the animals would never catch smallpox.
Cows infected with the mild infection had a few weeping spots (pocks) on their udders, but suffered little discomfort. Milkmaids occasionally caught it from their animals and felt off-colour for a few days, but could then return to work unscathed.
Mr Jenner thought he would test the affect of cowpox as a vaccine by purposefully infecting someone with it, and then exposing them to smallpox so he could monitor their response.
What happened in the first challenge trial?
In May 1796 a milkmaid, Sarah Nelmes, came to Mr Jenner about a rash that had appeared on her hand. He diagnosed cowpox and Ms Nelmes confirmed that one of her cows, Blossom, had recently suffered from the disease.
Spotting his chance Mr Jenner asked his gardener’s eight-year-old son, James Phipps, to take part in the experiment. On May 14 he made a few scratches in the boy’s arm and inserted some skin samples from the rash on Ms Nelmes’ hand.
The boy then became mildly ill with cowpox, but recovered a few days later.
On July 1 Mr Jenner exposed his gardener’s son to smallpox, to discover whether his trial had been successful. Fortunately, the boy did not develop smallpox on that occasion, or the many times he was tested afterwards.
Source: The Jenner Institute
