Healthy adults aged between 18 and 55 will be among the first to try out a new potential coronavirus vaccine.
They'll be monitored to see whether the jab is safe, before it's then tested on the elderly.
The lead researcher at Oxford University previously said it has an 80 per cent chance of working.
Professor Adam Finn from Bristol University, who is helping with trials, isn't as confident.
"Most vaccines don't work, the ones that we try out only a minority come through and are successful in the end.
"I think this vaccine has a good chance of success, but I think we need lots of horses in the race to make sure at least a few reach the finishing line."
