Britain on Monday urged elderly people and volunteers from Black and Asian minority groups to sign up to a Covid-19 vaccine trial registry to boost efforts to find a working vaccine against the disease that offers protection against higher risk groups.
No Covid-19 vaccine candidate has yet been proven effective against the disease, but around 20 are in clinical trials.
Over 100,000 people have volunteered to take part in vaccine trials, Britain's business ministry said, but more volunteers are needed to make sure candidate shots work for everyone.
"Protecting those at risk is the only way we will end this pandemic," said Kate Bingham, chair of the UK Vaccines Taskforce.
"Getting 100,000 volunteers on board is a great start but we need many more people from many different backgrounds that we can call on for future studies if we are to find a vaccine quickly to protect those who need it."
The government said it was particularly keen for over 65s, frontline health and care workers and people from Black, Asian and minority ethnic backgrounds to sign up.
A study last week showed that minority ethnic groups were two to three times more likely to have had Covid-19 compared to white people in England. Disproportionate numbers of people from minority groups have also died from the disease.