Professor Robin Shattock, who leads Imperial College London's vaccine team, said its Covid-19 vaccine could be rolled out across the UK in the first half of next year if everything goes "really well".
The professor said that 15 volunteers had been vaccinated so far, and another 200-300 participants would be vaccinated in the "coming weeks", reports BBC.
"We anticipate if everything goes really well that we'll get an answer as to whether it works by early next year. And we have put in place the infrastructure to make that vaccine for the whole of the UK.
"So, assuming that the funding is there to purchase that vaccine, we could have that vaccine rolled out across the UK in the first half of next year."