Rapid Covid tests missed 60 per cent of known virus cases in Liverpool

Operation Moonshot rapid Covid tests missed 60 per cent of known virus cases in Liverpool trial, new research shows

  • A quarter of Liverpool’s 498,000 residents were tested with later flow devices
  • The trial yielded 897 positive results – but figures suggest it missed 60% of cases 
  • Evaluation of the pilot showed which demographics participated in the trial 
  • Young men from poorer backgrounds were the hardest to get hold of, it found  

Rapid Covid-19 tests used in an Operation Moonshot trial in Liverpool missed 60 per cent of positive cases, new research has revealed.

An evaluation of November’s pilot found lateral flow tests – which are being used to test lorry drivers trapped at Dover – failed to pick up the majority of positive cases.

Earlier this month it was revealed the tests, which can return results within the hour, were missing cases where people were carrying low levels of the virus. 

The British Army was sent out to Liverpool to run the testing pilot between November 6 and December 9, with hopes similar schemes could be run across the country as part of Operation Moonshot. 

Soldiers wearing PPE oversaw a mass testing trial in Liverpool throughout November, which saw thousands administer themselves with rapid-result lateral flow tests, under supervision

But analysis of 6,000 swabs taking in Liverpool revealed the Innova LFT device identified just two fifths of cases that were later confirmed to be positive via PCR testing – a swab method that requires analysis in a laboratory to achieve a result. 

Given LFT’s low sensitivity, researchers say ‘caution should be exercised’ in how the tests are used, particularly in vulnerable settings ‘where the consequences of infection are severe’.

In these settings, LFTs should be used with, but not to replace, PCR tests, they say.

Prime Minister Boris Johnson and Emmanuel Macron last night agreed a deal to let lorry drivers into France, as long as they had received a negative test from the 30-minute lateral flow test. 

Liverpool’s mayor Joe Anderson was among the participants of the pilot, but a report as revealed that LFT’s failed to pick up 60 per cent of cases, warning that they should only be used alongside more reliable PCR tests

Lateral flow tests are portable and are able to give a result in under an hour, meaning they have been favoured for mass testing

It came after thousands of lorries were stranded in Kent due to France’s decision to close its border amid fears of a mutated coronavirus strain.

A report on Liverpool’s mass testing trial said there was no clear evidence that scheme had an impact on coronavirus cases or hospital admissions.

It also found people from poorer backgrounds were half as likely to take a test, but twice as likely to be positive. 

A PCR test can cost upwards of £180 per person, with the swab needing to be processed in a lab. 

The UK, on the other hand, favours faster tests which are not lab based and give a result within 15 minutes.

These rapid coronavirus tests, known as lateral flow tests, are ones that can be done on the spot using portable equipment.

They are faster and cheaper than lab-based PCR tests, which the government uses to diagnose people, but are less accurate. 

Young people, particularly males, were the hardest to reach, and people in areas of low internet use were less likely to take up a test and more likely to test positive. 

Fear of not having adequate support to isolate, and misinformation over test accuracy were found to be ‘significant barriers’ to participation.

Professor Iain Buchan, who led the evaluation, said: ‘The sensitivity of the lateral flow device was less than expected at 40%, but the time and scale gained by having a low-cost test that returns results within an hour without a laboratory is a valuable new tool for tackling Covid-19.

‘Younger people, particularly men, from deprived areas were harder to reach, as expected. But digital exclusion was a bigger barrier than we expected.’

Liverpool’s director of Public Health, Matthew Ashton, said the pilot had been ‘hugely valuable’, adding: ‘A significant proportion of the population embraced the idea wholeheartedly, helping identify a substantial number of asymptomatic people who otherwise would have been unknowingly spreading it to others.’

A third of all cases detected in Liverpool between December 11 to 17 were via LFTs after the military handed over the reigns to local agencies on December 3.

Health Secretary Matt Hancock said on Wednesday that 116 local areas have signed up for community testing, with conversations ongoing with more, calling the rapid tests ‘extremely effective’ at finding cases.

He said the Liverpool assessment ‘shows how effective this can be’, adding: ‘I’d urge anyone who has the opportunity to take part to protect their local area.’

Concern over lateral flow testing’s accuracy comes after Boris Johnson and Emmanuel Macron agreed the devices could be used to test lorry drivers currently stranded at Dover 

Paul Hunter, Professor in Medicine at the Norwich School of Medicine, University of East Anglia, said it did not seem as though the pilot had ‘much if any impact’.

He continued: ‘Indeed with the low overall take up rate, the even lower up take in populations with the higher infection rates and the poorer than expected sensitivity of the lateral flow test in use, I doubt that such as scheme as that piloted in Liverpool will have more than a marginal impact on the spread of the Covid-19 in the UK.

‘Whether such population-wide testing of asymptomatic individuals could be improved to the point that it would have a valuable impact on the epidemic especially with the more infectious new-variant must be uncertain.’

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