'Inaccurate' rapid COVID tests could make outbreak worse, expert warns

George Martin
·3-min read
OXFORD, ENGLAND - DECEMBER 12: A self-test kit for SARS-CoV-2 in a students college room on December 12, 2020 in Oxford, England. The university concluded its Michaelmas term largely under England's nationwide lockdown that curtailed in-person instruction and suspended extracurricular events. Like other university students in the UK, those traveling home for the Christmas break were asked to take "lateral flow" covid-19 tests, with a positive result requiring a confirmatory PCR test. Oxford students are expected to return for the Hilary term, which will have a staggered start for in-person teaching. Returning students are being advised to take three covid-19 tests upon return: the day they arrive, three days later, and again on the tenth day. (Photo by Laurel Chor/Getty Images)
A lateral flow test given to a student at Oxford University before Christmas. (Getty)

Rapid COVID tests could make the coronavirus outbreak worse by providing large numbers of false negatives, an expert has claimed.

Professor Jon Deeks, of the Institute of Applied Health Research at the University of Birmingham, raised questions about the quality of lateral flow COVID-19 tests.

The 15-minute tests, which the UK has spent more than £600 million on as part of its Moonshot testing plan, are set to be rolled out to secondary schools and colleges as term starts in January.

But according to Prof Deeks, despite around 7,100 students coming forward for asymptomatic testing before Christmas at Birmingham University – only two cases were found, and around 60 positive cases may have been missed.

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He said the results were “concerning” and raised concerned about the proposed rollout before term restarts after Christmas.

“We probably found two students and missed 60 with this test because of its poor performance,” Prof Deeks told BBC Radio 4’s Today programme.

Asked what would happen if the tests were used in schools, he said: “Well we’ll be allowing teachers and students to stay in school who had COVID, we’d be missing people who’ve got COVID.

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“The worst thing is actually the proposal that students when they’re in a class where one child has had COVID they stay in the school and are tested with this test until they go positive, because inevitably there’ll be students left in that class who become infectious and infect others, so we’ll end up with outbreaks in the school which wouldn’t happen with our current policy of sending kids home.”

He added: “Anything like this where we’re taking a new unknown test which has very little data as to how it works anywhere, it must be evaluated in its intended use setting before it’s rolled out across the country.”

“It might possibly be better in schools but the data are emerging that this test isn’t working well anywhere in asymptomatic people.

People carry out asymptomatic testing using lateral flow antigen at a test centre at Edinburgh University ahead of students being allowed to travel home for the Christmas holidays. (Photo by Andrew Milligan/PA Images via Getty Images)
People carry out asymptomatic testing using lateral flow antigen at a test centre at Edinburgh University. (Getty)

“It’s an imperfect test and when you have an imperfect test you have to use it so carefully to make sure you don’t mislead people and there’s a big risk this test is going to give a lot of false reassurance which inevitably will lead to more COVID disease.”

Dr Susan Hopkins, chief medical adviser to NHS Test and Trace, previously admitted there had been "false negatives" but stressed the mass testing policy was a "game-changer".

Prior to the pre-Christmas rollout, Dr Hopkins said that the lateral flow tests had "limitations" but said they were helping diagnose asymptomatic cases that would otherwise have gone undetected.

She added: "What we are doing here is case detection. We are not saying people do not have the disease if their test is negative.

"We are trying to say [to people who test positive] 'You do have the disease and now we want you to go and isolate for 10 days.' That is a whole different game-changer."

Prime minister Boris Johnson had hoped that his Operation Moonshot testing plans would be key to catching asymptomatic patients and keep the epidemic manageable until the most vulnerable are vaccinated.

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