Lateral flow tests detect more than 37,000 asymptomatic Covid-19 cases

More than 37,000 people with a symptomless Covid-19 infection have been detected through rapid lateral flow testing, the chief medical adviser for NHS Test and Trace has said.

Dr Susan Hopkins said the devices, which can give results in less than 30 minutes, were being rolled out across the country to enable those with no coronavirus symptoms to be tested.

Lateral flow tests are regularly used by NHS staff and were the main method of testing during a mass pilot scheme in Liverpool, but some experts have questioned their accuracy.

Coronavirus Mon Jan 18, 2021
Coronavirus Mon Jan 18, 2021

Dr Hopkins was asked at a Downing Street press briefing on Monday about the availability of the devices for teachers and supermarket workers who are yet to receive the Covid-19 vaccine.

She said: “We are rolling out lateral flow devices throughout the country through community testing sites and also in workplaces to allow people to get tested where they are asymptomatic to reduce the spread of disease.

“We’ve detected more than 37,000 individuals through lateral flow tests over the last number of weeks and we will continue to roll them out rapidly as an additional tool to help get this virus under control.”

There are two main types of test being used in Britain to detect cases of Covid-19.

PCR tests are swab tests of the nose and throat, which are assessed in a lab setting.

Lateral flow devices are quick turnaround tests, which can be performed without the need for laboratory assessment.

Jon Deeks, professor of biostatistics at the University of Birmingham, has previously argued people should not be told that lateral flow tests are “better than they are”.

The lead researcher of the Cochrane Review of Covid-19 diagnostic tests called for the Government to highlight the message that a negative test does not exclude disease.

"We call on the government to pause the rollout of rapid asymptomatic testing using the Innova test until clearer messaging on the risks of negative results can be developed" @deeksj@DrMikeWGill@angelaraffle

— The BMJ (@bmj_latest) January 12, 2021

Prof Deeks told Sky News that the lateral flow tests in Liverpool “missed 60% of the cases which would have been picked up by PCR”.

He said: “I think there’s an anxiety that, if we tell people the truth as to how bad this test is, people won’t bother getting it.

“But we have to do the truth – we can’t tell people that the test is better than it is.”

It came as an article published in The BMJ called for the Government to rethink the rollout of the lateral flow tests.

The article, published in the journal by Prof Deeks and colleagues, said extending the programme – which could potentially involve at-home use – could cause “serious harm”.

“We call on the Government urgently to change course,” the authors wrote.

They added: “Low test accuracy would be less dangerous if people being tested and the public at large received accurate information about the risks and implications of a false negative result.

“Instead they are being misled.”

Lateral flow devices used by the UK Government go through a rigorous evaluation by the country’s leading scientists, a Department of Health and Social Care spokesperson said.