The Government has confirmed challenge trials where healthy volunteers are infected with coronavirus will be allowed to go ahead in the UK.
Up to 90 volunteers will receive a dose of Covid-19 through their nose – a common transmission route – to find the ‘lowest possible safe dose’ before an infection is triggered.
It is hoped the trials will ramp up efforts to develop a vaccine, which is not expected to be made available until the first four months of next year at the earliest.
During the trial, set to start in January, the volunteers will stay at a specialist diseases clinic in the Royal Free hospital, London, where their symptoms will be closely monitored. Results are expected in May this year.
Professor Peter Openshaw, from Imperial College London, said the study aims not to get people ill but to ‘get the virus to replicate in the nose’.
‘We think that by taking every precaution we can really limit the infection and then we should be able to do it quite safely given the vast amount of experience that we have in this field,’ he said.
Challenge trials were pioneered in the 18th century by scientist Edward Jenner who exposed the eight-year-old son of his gardener to a virus to establish whether his experimental vaccine was effective.
Up to 90 volunteers will receive a dose of the virus through their nose at a specialist clinic in London. Scientists want to find the lowest possible dose required to trigger an infection (stock)
The volunteers are aged between 18 and 30 – the group thought to be least at risk from SARS-CoV-19.
After receiving a dose, they will be required to stay at the clinic for two-and-a-half weeks while their symptoms are monitored. This is also to stop them spreading the virus in the wider community.
Professor Openshaw told BBC Radio 4’s Today programme the trials could give a ‘really firm idea’ of whether a vaccine will work and how it will work.
‘There are so many vaccines now in field trials in the Phase III trials as we call them – which determine whether the vaccine is actually effective at preventing infection – but I think the vaccines that come through in the next three or four months won’t actually be the vaccines that we’re using in two to three years time.
‘So we need ways of aligning new vaccines against vaccines of proven efficacy and determining what it is that makes them work.’
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
through the nose through the nose to establish what the lowest possible dose is that can trigger an infection.
It is hoped the challenge trials – where volunteers are exposed to the virus – can speed up the development of a vaccine, which they think will not appear until this year.
‘lowest [possinbel safe dose’.
The challenge trials
Peter Openshaw, prof of experimental medicine at Imperial Colleg eLondon
‘The aim of these studies is not to get people ill but to get the virus to replicate in the nose, that’s really the end-point. We think that by taking every precaution we can really limit the infection and then we should be able to do it quite safely given the vast amount of experience that we have in this field.’
trials will be allowed to go ahead to establish how much of the virus is required to trigger an infection.
Up to 90 healthy volunteers will be exposed to the virus.