Public Health England Approves Two Antibody Tests

Peter Russell

May 15, 2020

Editor's note, 15th May 2020: This article was updated with news of a second approved test.

A second manufacturer has gained approval for an antibody test to help determine if a person has been exposed to the SARS-CoV-2 virus and whether they have developed antibodies against the virus.

US-based Abbott joined Swiss pharmaceutical company Roche in getting backing from Public Health England (PHE).

Scientists at a PHE facility confirmed the positive assessment on the Roche tests during trials last week.

The results have been described as a "very positive development", although some experts called for more details.

Abbott Offers 5 Million Test Capacity for the UK

Today it emerged that Abbott's system had also produced accurate results in trials.

The company said that its SARS-CoV-2 immunoglobulin G (IgG) test had been evaluated by UK public health bodies, which had "communicated evaluated specificity results between 99.73% and 100%".

It said it had the capacity to provide 5 million tests to the UK each month with immediate effect.

The Government and health officials have been hoping that accurate antibody tests will help track the spread of COVID-19 and help ease the lockdown. However, questions remain about its usefulness.

At Thursday's daily Downing Street briefing Prof Jonathan Van-Tam, England's deputy chief medical officer, said: "It's going to take us time to understand whether the antibodies, in all cases, protect against infection." He added: "The final science question is how long into the future do the antibodies last for? It is not automatic by any means that these are going to be lifelong."

PHE said its scientific experts had been evaluating a number of lab-based antibody assays, including those produced by Roche and Abbott using serum samples.

It said its trial results had been shared with the manufacturers, but that evaluation work was ongoing and results would only be published once all work has been completed and the results had been thoroughly reviewed.

Prof John Newton, national coordinator of the UK Coronavirus Testing Programme, said: "We were confident that good quality antibody tests would become available when they were needed.

"Last week, scientific experts at PHE Porton Down carried out an independent evaluation of the new Roche SARS-CoV-2 serology assay in record time, concluding that it is a highly specific assay with specificity of 100%.

"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."

Prof Van Tam said: "I anticipate that it will be rapidly rolled out in the days and weeks to come as soon as it is practical to do so. I also anticipate that the focus will be on the National Health Service and on carers in the first instance."

He added: "This is a good test that will stand us in good stead moving forwards, and I think it will be incredibly important as the days, weeks, and months go by."

The Elecsys Anti-SARS-CoV-2 serology test developed by Roche has claimed specificity greater than 99.8%, and sensitivity of 100%.

According to the company, the test is an immunoassay for the in-vitro qualitative detection of antibodies (including IgG) to SARS-CoV-2 in human serum and plasma.

After a blood sample is taken, the test, which is based on an in-solution double-antigen sandwich format, can detect antibodies to the novel coronavirus causing COVID-19.

Hospitals and laboratories would be able to run the test on Roche's cobas e analysers.

The company said that because of its large global manufacturing capabilities it would be able to deliver millions of testing kits each month.

Game Changer?

Experts commented on the Roche test announcement.

Matt Keeling, professor of populations and disease at the University of Warwick, told the Science Media Centre: "This could be a complete game-changer. The key is the very high sensitivity and specificity.

"High sensitivity means that if you've previously had coronavirus the test will correctly identify this; this likely means that such individuals are at lower risk of catching the virus again."

Dr Alexander Edwards, associate professor in biomedical technology at the University of Reading, commented: "At the moment we don't know if having antibody will fully protect from infection and for how long, so a specific test still doesn't answer all the questions.

"But false positives are still always a concern so it's vital to know that such laboratory antibody tests can achieve this accuracy."

Other experts had questions about the technology and the way it was tested.

Prof Sheila Bird, from the University of Cambridge, wanted to see more details about the independent evaluation at Porton Down. "Meta-analysis of the results from evaluations conducted by Roche and independently at Porton Down should give consistent and precise overview of specificity and sensitivity of the antibody test, both with 95% confidence intervals," she said.

"Results should be reported publicly in a statistically appropriate manner for this important breakthrough."


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