Thousands of people who test positive for Covid-19 will be offered free antibody in a bid understand how many people catch the virus twice.
The Government today launches the first nationwide antibody surveillance programme, which will see patients screened for antibodies immediately after a positive PCR test.
It’s hoped the data will help scientists obtain “vital” data on people who catch the virus despite already having antibodies from being vaccinated or a previous bout of Covid.
Some 87% of people aged 16 and over have now received their first COVID-19 vaccine dose, while 76% have had their second dose.
It comes as an expert warned the UK must not take its’ “eye off the ball” with vaccinations, warning the virus could come "roaring back".
Dr Chris Smith, consultant virologist and lecturer at Cambridge University, told the BBC: “We all agree that (the pandemic) is not over until it is over in every corner of the world, because otherwise it will just come roaring back.”
He added: “One must not take one's eye off the ball here because it would be very easy to unstitch all of the good work we've done so far if it turns out with time we do lose immunity because the vaccines wane in their effectiveness.”
Some 37,314 people tested positive for Covid-19 on Friday, bringing the weekly total to 219,350.
On the same day, there were 858 people admitted to hospital suffering from the virus, with 114 deaths within 28 days of a positive result.
In the last week, 688 people died within 28 days of a positive result, a 10.4% increase compared to the previous week.
Of those who test positive for coronavirus, up to 8,000 will be sent two finger prick antibody tests to complete at home and send back for analysis.
The first must be taken as soon as possible after the positive result, and the second must be taken 28 days later - to measure antibodies generate through infection.
The Department of Health and Social Care said it will be the first time antibody tests have been made freely available to the general public - and could give further insight into the effectiveness of vaccines on new variants.
Health Secretary Sajid Javid said the programme will build on the "massive wall of defence" that is the UK vaccination programme.
"Our new national antibody testing will be quick and easy to take part in," he said.
"By doing so you'll be helping strengthen our understanding of Covid-19 as we cautiously return to a more normal life.
"I'm proud to see all parts of the UK uniting around this new initiative and working together to arm ourselves with even more valuable insights into how Covid-19 vaccines are protecting people up and down the UK."
UK Health Security Agency chief executive Dr Jenny Harries said: "We are rolling out antibody testing across the UK to gain vital data into the impact of our vaccination programme and on immune responses to different variants of Covid-19.
"This innovative programme is only possible thanks to the thousands of people who continue to help with studies on vaccine and treatment effectiveness each week.
"The best way to protect yourself and those around you is by getting vaccinated.
"I encourage anyone who has not yet come forward to book their first and second jabs."
