More than 100,000 people have signed up to take part in future NHS trials of a coronavirus vaccine - but more volunteers are needed, researchers say.
They want as many people as possible to enrol, to speed up their efforts to find a safe and effective jab.
And they are particularly looking for more volunteers from the "high-priority groups" disproportionately affected by the virus - those belonging to ethnic minorities or aged over 65.
Volunteers can register online.
Kate Bingham, who chairs the UK's vaccine taskforce, said: "These trials are safe, please sign up.
"The quicker we get the clinical trials enrolled, vaccinated and get the results, the quicker we can get a vaccine."
A number of trials are expected to begin this autumn in the UK.
By the end of the year, there could be at least half a dozen different coronavirus vaccines in clinical trials, including one being developed by Oxford University that is already in an advanced stage of testing.
And hundreds of thousands of volunteers will be needed.
They will be given either one of the test vaccines or a placebo jab and then visit a hospital, or other research site, a few times over six to 12 months, where they will:
- be told about the research study
- have the chance to ask any questions
- have blood tests
Between visits, they will be asked to tell the research team about any symptoms they have and may need to keep a diary or take weekly throat and nose swab tests at home.