An antibody test to show whether someone has had coronavirus has passed stringent tests carried out by Public Health England, paving the way for its widespread adoption.
Discovering that an individual has had the virus and produced antibodies is seen as a key weapon in the armoury for restoring normal life after the lockdown. Antibodies are thought to confer a degree of immunity from future infection, although scientists differ on how long-lasting such effects may be.
Until now, however, there have been questions over the accuracy and reliability of such tests.
On Wednesday John Newton, national co-ordinator of the UK Coronavirus Testing Programme, confirmed that PHE had given the green light to an antibody test made by Swiss pharma company Roche.
“We were confident that good-quality antibody tests would become available when they were needed,” he said. The news was first reported by the Telegraph.
Last week, scientific experts at PHE’s hub at Porton Down carried out an independent evaluation of the test “in record time”. They concluded that the test had correctly identified the presence of antibodies in 100 per cent of the affected blood samples, making it “highly specific”. Tests with a low specificity risk giving people false positive results.
Prof Newton added: “This is a very positive development because such a highly specific antibody test is a very reliable marker of past infection. This in turn may indicate some immunity to future infection although the extent to which the presence of antibodies indicates immunity remains unclear.”
A working test could also help identify people who have been infected by the virus but not developed any symptoms.
Since PHE is not a regulator, any decision on deploying the test at scale in the UK will be taken by the Department for Health and Social Care. Roche said it was working closely with the NHS and the government to enable a “phased rollout of the test as soon as possible”.
The company said it would be able to provide hundreds of thousands of tests to the UK per week. The health department could not be reached for comment late on Wednesday night.
Roche’s lab-based antibody test had already gained approval from the US Food and Drug Administration, but NHS Trusts and the UK government have looked to PHE for guidance on which tests to adopt.
The Roche test is different from the finger-prick self-testing kits that ministers had said in March would be soon be rolled out to the public. There are still widespread concerns over the accuracy of these rapid antibody tests — though the government has asked a consortium of companies to develop a version that could be used for home testing.
This month, the government revealed it had recouped £70m of the £92m it spent on the 17.5m inaccurate Covid-19 antibody tests it ordered from nine suppliers this year.
PHE has been using lab-based antibody tests made by German company EuroImmun as part of its population-level surveillance work of the virus. The goal is to use this information to inform choices on social distancing and other strategies.
EuroImmun’s test, which has been used to screen blood from several thousand people, is considered accurate enough to be used to look for population-level trends but not accurate enough to be used to give test results for individuals.