British health chiefs last night finally approved an antibody test, after several weeks of disappointment in the UK’s plan to roll-out the game-changing kits.
Ministers are in talks with Swiss firm Roche to buy millions of the tests, which will be given to NHS and social care workers before being rolled out wider.
Here, MailOnline reveals everything you need to know about Roche’s antibody test, from how accurate it is to how it will be used in the UK.
Public Health England have announced that a new coronavirus antibody test by Swiss pharmaceutical company Roche has been found to be 100 per cent accurate. The FDA in America has already issued emergency use approval
WHY IS ANTIBODY TESTING IMPORTANT?
WHAT IS AN ANTIBODY TEST?
Unlike tests to diagnose diseases, antibody tests show who has been infected and recovered.
The body makes antibodies in response to many illnesses and infections, including other coronaviruses. New blood tests are being developed to identify antibodies unique to SARS-CoV-2, the official name of the new coronavirus.
The tests look for two kinds of antibodies: immunoglobulin M (IgM) and G (IgG). The body quickly produces IgM antibodies for its initial attack against infections. It makes IgG antibodies more slowly and retains them longer; IgG antibodies suggest possible immunity.
WHAT IS THE DIFFERENCE BETWEEN RAPID TESTS AND ASSAYS?
Some companies are developing finger-prick tests that get results in minutes. These are called immunoassays and will form the basis of home testing kits.
Others are developing far more accurate tests called enzyme-linked immunosorbent assays (ELISA) that require sending blood samples to a lab for analysis.
HOW CAN ANTIBODY TESTS HELP END LOCKDOWNS?
Antibody tests can help calculate what portion of the population has already been infected, as well as whether infections were mild or severe.
Governments and companies could use antibody tests to determine who would most likely be safe to return to work and public interactions, and whether it is safe to lift stay-at-home orders all at once in some regions or in stages based on infection risk.
People with negative antibody tests or very low antibody levels would likely have higher risk of infection than people with high antibody levels.
DO ANTIBODIES TO THE NEW CORONAVIRUS CONFER IMMUNITY?
While antibodies to many infectious diseases typically confer some level of immunity, whether that is the case with this unique coronavirus is not yet known.
And how strong immunity might be, or how long it might last in people previously infected, is not clear. With some diseases like measles the immunity can be lifelong. With others, immunity can wane over time.
Scientists cannot know with certainty that reinfection is not possible until further research.
Antibody tests could inform not just lockdown exits, but the best approach to treatments and vaccines.
HOW WILL IT BE USED IN THE UK?
Ministers are now in talks with Roche to buy millions of the kits, which are lab-based tests.
The blood sample kit, which can be processed by machines already used in NHS labs across the country. Medics can get results in just 18 minutes.
Health minister Edward Argar today said the tests would mainly be given to NHS and social care workers to start with – but did not say when testing would start.
Insiders say it is also likely to play a role in the government’s ‘surveillance’ schemes, which will help track how far the virus has spread in Britain.
Ministers are currently clueless about the true size of Britain’s outbreak because health chiefs abandoned a mass-testing regime early on in the crisis.
One of the current antibody schemes already underway has seen nurses take blood samples from a thousand households.
Early results – not yet published by officials – suggested up to four per cent of Britain has developed antibodies to the coronavirus.
CAN I USE THE ROCHE TEST MYSELF?
The Roche test, which is called Elecsys, is simply not designed to give people a result in the comfort of their own home.
Ministers have promised ‘pregnancy-test’ style kits, which would see Brits take their own blood sample and get a result in as little as 10 minutes.
But no DIY test – scientifically called an immunoassay – has yet to be approved by officials despite promises one would be available back in March.
One firm – awarded millions of pounds by the government to produce home-testing kits – hopes to have its product ready by the start of June.
Mologic’s serology test will be available for Britons to purchase online, from retailers such as Boots and Amazon, according to reports.
It has not yet been approved by the Bedfordshire-based company is in ‘urgent talks’ with ministers to fast-track approval, The Telegraph says.
HOW MUCH WILL THEY COST THE GOVERNMENT?
Roche – which plans to produce millions of the kits each month – has not revealed how much the antibody test will cost to purchase in bulk.
The government is understood to be in negotiations with Roche to buy millions of the Elecsys tests – but the exact amount is unclear.
Britain did, however, pay two Chinese firms around £16million for 2million antibody tests that failed strict accuracy tests – suggesting each kit cost around £8.
No details of any deals struck between Roche – based in Basel – and other countries have been made public.
This means it is not known whether Britain will pay more or less than other nations desperately seeking the antibody tests as draconian lockdowns are eased.
WILL PRIVATE FIRMS BE ABLE TO BUY THE TESTS?
Officials have yet to come forward with a concrete plan about how the tests will be used, or whether private firms will be able to buy them.
Many companies keen to restart operations want to use antibody testing kits to work out how much of their staff may be immune to the virus.
Insiders say it is unlikely the Roche tests will be available to purchase privately, at least initially.
This is because officials wouldn’t be able to access the data they desperately need to plot the spread of the virus.
THE TIMELINE OF UK’S ANTIBODY TESTING DEVELOPMENTS
March 25: Professor Sharon Peacock, the director of the national infection service at PHE, told MPs antibody kits would be ready within days.
But confusion was sparked when chief medical officer Professor Chris Whitty told revealed the tests would not be ready to buy online within days.
March 26: Professor Yvonne Doyle, medical director at PHE, told MPs she expected home antibody tests to be available within a ‘couple of weeks’.
April 1: In the Downing Street press conference, Professor Doyle disputed the claim that PHE was ‘dragging its feet’ in approving antibody tests.
She said: ‘The important thing about theses antibody tests, this is not a matter of dragging our feet, it’s important that the test is valid, that it does what it says it does.’
April 6: Sir John Bell, one of the Oxford University team evaluating antibody tests for the government, revealed none of them performed well.
April 17: The New York Times reported that Britain was seeking a £16million refund after two antibody tests it had bought from Chinese companies were not accurate enough to be rolled out.
April 21: University of Oxford experts published anonymised results of the nine tests the government had bought – they showed all were deemed too weak to use.
Their sensitivity – ability to correctly spot people who had had the disease – ranged from 70 per cent to just 55 per cent.
May 3: US regulators gave the ‘game-changing’ antibody test made by Swiss pharmaceutical giant Roche the green light.
May 4: German health bosses announce a deal with Roche to buy 3million of its kits in May, as well as 5million per month from June.
May 13: Public Health England follows suit, approving the test to be used. It was revealed that health chiefs were planning to buy millions.
It remains unclear exactly how much the lab-based tests could cost, if and when they can be purchased.
WHO ELSE HAS APPROVED THE ROCHE ANTIBODY TEST?
Roche first announced it was developing the antibody on April 17, revealing it had plans to put it on the market in early May.
At the time, it announced it was working the US health regulator the Food and Drug Administration (FDA) for an ’emergency use authorisation’.
The FDA gave it the green light on May 3, allowing laboratories across the US to use it even though it has yet to be formally approved.
Roche also announced that the blood sample kit was also granted the vital ‘CE mark’ that shows it is safe to use within the EU.
German officials already signed a deal at the beginning of May to buy five million of the Roche kits every month.
Roche said the amount of tests it would be able to make each month for the US and countries accepting the CE mark would be in the ‘high double-digit millions’.
SO WHY HAS IT TAKEN THE UK SO LONG TO APPROVE ANY TEST?
Sir John Bell, an immunologist at Oxford University involved in evaluating antibody kits for the government, admitted approving tests takes ‘longer than it should’.
He suggested officials wanted to be completely sure that the tests were accurate, telling BBC Radio 4 Today’s programme: ‘I think you have to be a bit cautious.’
Sir John accepted it has ‘taken a week or two longer than it might have’, while other experts have said ‘every day counts’ amid a pandemic.
But he pointed out the failure of DIY antibody tests, which were described as ‘terrific’ and offered hopes of a way out of lockdown – but none turned out to work.
Professor Paul Hunter, an infectious disease expert at the University of East Anglia, told MailOnline: ‘In the grand scheme of things, 11 days would be nothing.’
But he added that ‘when you are in a situation like this when every day counts, it is indeed concerning’.
HOW ACCURATE IS THE TEST?
As long as it is used at least 14 days after someone has developed symptoms, it has a 100 per cent sensitivity rate, Roche claims.
Sensitivity is the rate of all positive samples that are truly positive. For example, if a test has an accuracy rate of 99 per cent, it means 99 out of every 100 people who test positive have actually been infected.
The other one person, however, would have been given an inaccurate result – known as a false negative result.
The Roche test also has a ‘specificity’ of 99.8 per cent, meaning it generates very few ‘false positives’ – when it indicates someone has been infected when they have not.
For every thousand people who take the test only two will be given a false positive result, according to its claim.
Sensitivity is considered the area authorities can afford to compromise on because testing errors in that area lead to false negatives – people being told they haven’t had the disease when they actually have – which would lead to relatively few consequences for most.
False positives, however, caused by poor specificity, may lead people to believe they are immune when they’re not, causing their behaviour to become riskier, or to receive treatment that they don’t need.
HOW COME THIS ONE WORKS WHEN OTHERS HAVE FAILED?
Roche scientists have managed to develop a test that only picks up the virus that causes COVID-19, scientifically known as SARS-CoV-2.
Previous tests assessed struggled to differentiate COVID-19 antibodies from four other types of human coronaviruses which cause the common cold.
The body makes antibodies in response to many illnesses and infections, including other coronaviruses.
But independent experts have also called for transparency over the results, which haven’t been made publicly available.
Professor Carl Heneghan, from Oxford University, said: ‘Without seeing the study methods and the data it’s impossible to verify these claims of accuracy.’
Professor Sheila Bird, a bio-statistician at Cambridge University, also called on the government to reveal the study design to allow scientists to scrutinise the work.