Seventeen sites, including in the West Midlands, are being used for the leading phase three study of an experimental coronavirus vaccine developed by pharmaceutical company Janssen.
While it is a welcome step forward in the race to discover a safe and effective cure, there are warnings that a vaccine may not be 'one-size-fits-all'.
Researchers leading the trial in the Midlands today urged people to keep volunteering for studies to ensure people have access to different types of vaccines that work for them.
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Dr Christopher Green, principal investigator for the trial at University Hospitals Birmingham NHS Foundation Trust, said: “We need to fully evaluate different vaccine technologies to answer important questions on how we can best protect our health and the health of our communities from Covid-19.
"As ever, we need the help of the public to do this and we work hand-on-hand with our volunteers to complete these clinical trials.
"It’s so important that people come forward to help us investigate vaccines for the benefit of everyone.”
For the two-dose Janssen study, researchers are aiming to recruit around 6,000 UK participants – from a total of 30,000 people globally.
Recruitment will complete in March next year and the study, testing the safety and effectiveness of the experimental vaccine, will last for 12 months.
The shot uses a harmless cold virus to deliver the spike protein of the coronavirus into the body, which scientists hope will prompt an immune response.
The UK government has developed a portfolio of six different vaccine candidates and secured access to 350 million doses to date.
To date, more than 300,000 people have signed up to the NHS Covid-19 Vaccines Research Registry to take part in vital coronavirus vaccine studies.
Several more phase three studies for potential vaccine studies are expected to start over the next six months and researchers need more volunteers to sign up.
In particular the NHS Covid-19 registry needs those who are most vulnerable to the effects of coronavirus, including frontline health and social care workers and people from black, Asian and ethnic minority backgrounds.
People wishing to volunteer to support clinical trials can sign up for information on Covid-19 vaccine trials with the NHS Covid-19 vaccine research registry, developed in partnership with NHS Digital.
Anyone living in the UK can sign up online to take part in the trials through the NHS, giving permission for researchers to contact you if they think you’re a good fit.
Once you sign up, you can withdraw at any time and request that your details be removed from the registry.