Covid lateral flow tests only pick up 49 per cent of infections because they fail to catch people carrying low level of the virus, researchers believe - blowing a massive hole in Government's mass testing strategy
- Findings of a pilot suggest lateral flow tests are only 50 per cent reliable
- Lateral flow test produced by US-based Innova only picks up 48.89 per cent
- It contradicts earlier lab tests which found a sensitivity of 76.9 per cent
- Last week the Government promised these tests would help families reunite Coronavirus lateral flow tests only pick up 49 per cent of infections because they fail to catch people with low levels of the virus, researchers have found.
The findings of a pilot of 3,199 people has blown a hole in the Government's mass testing strategy, which featured plans to hand out millions of 30-minute tests to allow Britons to go back to living life normally, it was revealed yesterday.
The lateral flow test produced by US-based Innova only pick up 48.89 per cent of active infections, according to a University of Liverpool pilot programme, reported the Financial Times. It contradicts earlier lab tests, which found the test had an overall sensitivity of 76.8 per cent, rising to 95 per cent in individuals with a high viral load.
The findings of a pilot of 3,199 people has blown a hole in the Government's mass testing strategy, which featured plans to hand out millions of 30-minute tests to allow Britons to go back to living life normally. Pictured, a lateral flow test is processed on December 8
The lateral flow test produced by US-based Innova only picks up 48.89 per cent of active infections, according to a University of Liverpool pilot programme, reported the Financial Times. Pictured, a student is tested at the University of Swansea
The pilot's results come after an audit by the Mail found four major care home chains and nine councils were refusing to use rapid tests for visitors, which establish whether they can be admitted to premises, due to concerns about their accuracy. Last week, following a Daily Mail campaign, the Government promised that millions of the 'lateral flow tests' would be rolled out to care homes by the end of next week so residents and families could be reunited.
It said visitors who tested negative for Covid would be allowed to hold loved-ones for the first time in months.
But major providers such as Bupa, MHA, Barchester Care and Anchor Hanover have all refused to trust the results of the tests.
Last week, following a Daily Mail campaign, the Government promised that millions of the 'lateral flow tests' would be rolled out to care homes by the end of next week so residents and families could be reunited. Pictured, a student at Swansea University is tested
A spokesman for Liverpool City Council has confirmed it won't be asking care homes to allow visitors until the tests' accuracy has improved.
They said: 'Although lateral flow testing is considered safe as an extra measure to protect staff as it relies on repeat testing, it was felt that it may not be safe enough to use on visitors to high-risk settings like care homes who may not have had repeat tests.'
The latest research was released yesterday by the Scientific Advisory Group for Emergencies (SAGE).
William Irving, professor of virology at Nottingham University, said some of the Government's edicts around mass testing were 'frankly ridiculous, like rolling out all these tests without proper validation.'
He added: 'We're doing all of this testing on asymptomatic people and there's no evidence that it's changing anything.'
A spokesman for Liverpool City Council has confirmed it won't be asking care homes to allow visitors until the tests' accuracy has improved. Pictured, a Swansea university student scans a barcode as part of the lateral flow test
The results of the pilot show the reliability of the tests cannot be trusted - as the two different tests of its effectiveness returned contradictory conclusions.
A Department of Health and Social Care spokesperson said: 'With up to a third of individuals with Covid-19 not displaying symptoms, broadening testing to identify those showing no symptoms and who can infect people unknowingly will mean finding positive cases more quickly and break chains of transmission.
'The country’s leading scientists have rigorously evaluated the Optigene LAMP test and Lateral Flow Test and confirmed the accuracy of the tests for asymptomatic testing.'
In a report on Liverpool's mass testing programme, which saw around half of the city's 500,000 residents get tested over the course of a month, officials branded the scheme a success.
Simple laws of statistics mean even a highly accurate test will get huge numbers of results wrong when used on millions of people
They wrote: 'Frequently tests perform slightly less well in the field than in perfect laboratory testing condition...
'In field evaluations, such as Liverpool, these tests still perform effectively and detect at least 50 per cent of all PCR positive individuals and more than 70 per cent of individuals with higher viral loads in both symptomatic and asymptomatic individuals.'
Someone's viral load is a way of quantifying how much of the virus they are carrying in their bodies. People with more are generally considered to be more likely to infect others because, as a result of having more inside them, they also shed more.
The tests were compared by using both types on the people who get tested through the official route. A PCR test is the lab test considered the gold standard, and the one currently offered to people who have symptoms of Covid-19.
The UK is spending more than £1billion on rapid coronavirus swab tests to try and achieve Operation Moonshot – an ambition of testing everyone in the country at least once per week.
In a TV briefing at the end of October Prime Minister Boris Johnson said: 'We now have the immediate prospect of using many millions of cheap, reliable and above all rapid turnaround tests.
'Tests that you can use yourself to tell whether or not you are infectious and get the result within ten to 15 minutes.
'And we know from trial across the country in schools and hospitals that we can use these tests not just to locate infectious people but to drive down the disease
Rapid testing was piloted in Liverpool but a report from the Department of Health – published after the scheme had been rolled out nationwide – found that the tests miss half of all positive cases
'And so over the next few days and weeks, we plan a steady but massive expansion in the deployment of these quick turnaround tests.'
He said they would be applied in 'an ever-growing number of situations' including in hospitals to testing 'whole towns and even whole cities'.
But scientists warn the tests aren't accurate enough for people to consider themselves Covid-free if they get a negative result.
Loughborough University's Dr Duncan Robertson said in a series of tweets about the Liverpool report: 'So... we have a mass testing regime that has large numbers of false negatives. The problem with this is that people may take tests, be told the test is negative, and then believe they are negative.
'This can put vulnerable people at risk, and those in the communities in which they reside, such as residents in care homes.
'The vital message is - if you have a negative test it does not mean you are not infectious or will not be infectious.'
OPERATION MOONSHOT WIDENED TO 67 AREAS OF ENGLAND
Mass rapid coronavirus testing being used in Liverpool will be rolled out across in nearly 70 more local authorities, the Health Secretary said this month.
Matt Hancock revealed areas including Nottinghamshire, Yorkshire and the West Midlands will receive the rapid Covid-19 tests.
London, Birmingham, Manchester and Coventry are also among the cities to get a batch of tests.
At least 600,000 lateral flow tests have been sent out across the UK to kick-start the next stage of mass coronavirus testing, which ministers hope could finally send the virus packing.
Mass coronavirus testing being used in Liverpool will be rolled out across 66 local authorities, the Health Secretary said
The antigen tests can tell if a person is currently infected with coronavirus - even if they have no symptoms - and the technology can give results within an hour.
Every resident in Liverpool has been able to get tested for the disease since Friday, when the major army-backed scheme was first launched. The city, home to 500,000 people, was the first to be involved with No10's ambitious 'Operation Moonshot' — a mission to screen millions of asymptomatic people every day.
Speaking on Sky News on November 10, Mr Hancock claimed 66 local authorities had already expressed interest in the mass-testing scheme. More are expected to sign up in the coming weeks.
Despite Mr Hancock saying it was 66 authorities, the Department of Health released a list of 67 authorities that will get the rapid tests.
He added: 'I can confirm we are rolling out the sort of mass testing we are seeing in Liverpool, and indeed we earlier piloted in Stoke-on-Trent, across 66 local authorities.
'Last night I wrote to the directors of public health of all local authorities in England saying we can make available these brilliant new lateral flow tests that give results in 15 minutes, and we can make them available to directors of public health right across the country.
'Sixty-six expressed an interest in the first instance, I'm now expecting a whole load more.'
Mr Hancock also said that mass testing, like a vaccine roll-out, would be across the UK not just England.
He added: 'The UK Government has bought the vaccine for the whole of the UK and it will be rolled out fairly across the whole of the UK with the same prioritisation no matter where you live in this country.
'The same goes for mass testing, making sure we roll that out across the whole UK.'
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