A new coronavirus test being developed in the UK could provide crucial insights into how the illness spreads, according to infectious disease experts.

The swab test currently being used around the world to detect COVID-19 determines whether a person carries the virus.

But now a number of countries are in the process of verifying a blood test which can detect if someone has been cleared of coronavirus.

That test detects antibodies that are produced a week or two after someone has become infected with the virus and are part of the immune system's response to the illness.

Image: The blood test will not replace the swab test being used to detect the active virus

The antibody test has been rolled out for use in China and Singapore, where it has reportedly helped medical researchers track links between coronavirus cases.


Infectious disease expert Dr Katrina Pollock told Sky News the test could identify people who may not have known they had ever caught the disease.

"These are not new techniques - they are widely used for other diseases - but they are being applied to the new infection, and that is needed," she said.

"With them it's possible to tell who has come into contact with the virus even if they're not showing symptoms. It allows you to get a much broader estimate of how many people have been infected and that allows you to detect cases that maybe have mild or anti-symptomatic infections.

Image: Experts say the antibodies test will shed light on how the virus spreads among those with mild or no symptoms

"And that will tell us a lot about how the virus is spreading."

Because antibodies help protect the body from a virus, Dr Pollack said it could also reveal which type of people may be resistant to falling ill to the virus and which are more resistant.

This could be particularly useful for determining why so few children are becoming sick compared to adults, Dr Pollack said.

"We do need to understand what is happening with children," she said.

"It may be that the number of cases in children is getting underestimated if they're not getting symptoms."

Public Health England has confirmed it is developing a blood test to fight coronavirus, but did not provide further details.

Sky News understands the test is currently being checked for reliability - which Dr Pollack said was important to ensure the tests do not risk finding the wrong coronavirus strain.

She said understanding how the immune system reacts to the virus had also helped her work in developing a vaccine for the disease, which was undergoing clinical trials.

Infectious disease expert John Lamont also praised the new blood test as a useful surveillance tool to better understand COVID-19.

"You could monitor people's antibodies levels over the years and see how long you would have that prevention in the blood to monitor reinfection," he said.

Mr Lamont is the head of research and development at Randox Laboratories, which has developed its own test that differentiates COVID-19 from nine other respiratory infections.

The blood test being developed in the UK is also on its way to Australia - where the chief medical officer reportedly said it was the only way to work out the true mortality rate of virus.

According to media reports, Professor Brendan Murphy pointed to Iran's reported infection numbers being far lower than reality, as the initial outbreak of mild cases went undetected.

NHS England has declared coronavirus a level four incident - the highest level of emergency preparedness planning.

It comes as confirmed cases in the UK rose to by 34 to 85.