Covid tests used on students ahead of Christmas ‘only detected three per cent of cases’
The lateral flow tests missed students with Covid and gave them a negative result
Uni students with Covid may have wrongly received negative test results due to “rushed” and “inaccurate” testing ahead of the Christmas break, a University of Birmingham study has discovered.
Results from the study showed that lateral flow tests conducted on Birmingham students had missed positive Covid test results, which were discovered when students were retested with another testing method. The study shows that only 3 per cent of Covid cases were correctly identified.
Lateral flow tests involve a student taking a self swab which is then mixed with a “buffer solution” by a trained professional. The buffer solution is then dropped onto a lateral flow device, this indicates whether the disease is present in the individual in as little as 10-15 minutes.
Lateral flow tests were used by most universities to test students ahead of the Christmas break, including Durham, De Montfort, Bristol, Leeds, Leicester, Bath and Birmingham.
Professors from the University of Birmingham retested 710 students out of the 7,189 that took lateral flow tests. Initially, only two of these students appeared to have Covid from their lateral flow test results. When retested, this figure increased to eight. Given that only 10 per cent (710 students) of the total tested population (7,189 students) were retested, professors who conducted the study expect the number of students who were incorrectly given a negative test result may be much higher.
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“We found six false negative cases”, Professor Jon Deeks, who specialises in Biostatics at Birmingham, tweeted, “we thus estimate that we found two cases and will have missed 60 (because we only double tested 10 per cent).” This means that in line with the 10 per cent sample, as many as 60 positive cases could have been missed because of the low sensitivity of the lateral flow tests.
As well as the low sensitivity, which Professor Jon Deeks says is as small as three per cent, leading to false negatives (i.e when a student has Covid but falsely receives a negative result), lateral flow tests have demonstrated a high chance of false positives too.
Data from Scottish universities covering 40,000 students, including those at Aberdeen, Edinburgh, St Andrews and Glasgow, shows that 18 out of 31 positive results were incorrect. This means that 58 per cent of positives were false positives. This further decreases the accuracy of lateral flow tests, which have now proved to produce both false positives and false negatives.
However, the Department for Health and Social Care has said that the Scottish students who received false positives were not made to wrongly isolate as they took secondary tests to confirm the correct results. But with two tests required to assure a lateral flow test result is correct, Professor Deeks argues that they should be scrapped altogether.
“It wasn’t worth the effort”, Professor Deeks says of the lateral flow testing. “Five days, 30 people, converting our Great Hall to a testing centre. It may do a tiny bit of good, that’s the argument the government are putting forward, saying ‘well if we detect some cases that’s better than none’. But we’d be much better off perfecting contact tracing,” he told The Tab.
This is Prof Deeks’ recommendation for January, instead of repeating the mass testing seen in December, much of which involved lateral flow tests. “I think the money should be put into local contact tracing, get teams on the ground doing it. Put them in a testing center, start contact tracing from when the person is still there – you’d pick up the ones you’d missed by the flow tests.
“I’ve never seen the madness of what we’re doing [with these lateral flow tests]. They’re not ready, they’re not fit for purpose. I’d sooner rather them hang these tests on a Christmas tree in Trafalgar Square, that would be better.”
A spokesperson for the Department of Health and Social Care told The Tab: “The country’s leading scientists rigorously evaluated the Lateral Flow Test and confirmed the accuracy of the tests using a sample of over 8,500. Latest figures for similar settings showing sensitivity of 57.5% generally and 84.3% in people with high viral loads. This means they are accurate, reliable and successfully identify those with COVID-19 who don’t show symptoms and could pass on the virus without realising.
“With up to a third of individuals with COVID-19 not displaying symptoms, broadening testing to identify those showing no symptoms will mean finding positive cases more quickly and break chains of transmission.
“Anyone who tested positive with a lateral flow test during the university testing earlier this month would have been asked to get a confirmatory PCR test.”
Featured image via SWNS