The figures showed that the rapid tests identified just five out of 10 positive cases which had been detected by standard coronavirus tests, and seven out of 10 of those with high quantities of the virus.
Experts have called for an end to the use of rapid coronavirus tests in universities and care homes, after government figures from the mass testing programme in Liverpool revealed the tests missed 30% of those with a high viral load.
The figures showed that the rapid tests identified just five out of 10 positive cases which had been detected by standard coronavirus tests, and seven out of 10 of those with high quantities of the virus.
The rapid tests, also known as lateral flow tests, provide much quicker results than standard tests. This speed has led to their use in care homes to allow family members to visit, and in universities to allow students to return home for Christmas.
Allyson Pollock, professor of public health at Newcastle University, called for an end to the use of rapid tests in universities and care homes, saying that they gave “false reassurance”.
“Mass testing should be stopped, and sensible advice about symptoms and contact tracing should be given to students,” she said. “The lateral flow tests aren’t designed to be used on healthy symptomless people in the community, it says this in the information sheets from the manufacturers.”
Pollock also criticised the government for “burying” the statistics in a wider document on community testing. The statistics are mentioned in just one sentence in an 8,000-word government document on community testing.
“What’s really worrying is that the government still hasn’t published the evaluation of the mass testing in Liverpool bearing some of the key findings around the high proportion of false negatives so they’ve tucked away this extraordinary statement in the appendix,” she said.
Prof Jon Deeks of the University of Birmingham said the mass use of the rapid tests was “putting people at risk”.
“It is not the case that if you have a negative result from the tests, you don’t have Covid,” he said. “Everything says you should confirm them with the PCR tests.” The polymerase chain reaction swab test which is widely used in the UK is seen as the gold standard for detecting the virus but results take longer.
Dr Sian Taylor-Phillips, professor of population health at the University of Warwick, said she was most concerned that care homes “could be letting infectious people in”.
“My concern across all of the settings is whether we’re being honest with people that they could still be infectious, and that we’re not being fair not knowing that they’re putting their relatives at risk,” she said.
“There is an urgent need for a proper report on the results from Liverpool,” she added.
Prof Martin McKee of the London School of Hygiene and Tropical Medicine, who is a member of Independent Sage, said that he would be “very cautious about their use in care homes”, insisting that “nobody should rely on a single test”.
However, he said that the rapid tests could be effective in certain circumstances.
“With PCR tests, it can take several days from deciding to get a test to getting the results, and if people aren’t isolating in between, it is better to have a less sensitive test that is much faster. But the ideal thing is to have faster PCR testing,” he said. “The rapid tests do have a role, but it has to be the right role.”
A Department of Health and Social Care spokesperson said: “The country’s leading scientists have rigorously evaluated and confirmed the accuracy of the tests for asymptomatic testing.
“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.”
A Liverpool city council spokesperson said that those who had been given a rapid test had also been offered a confirmatory PCR test, and that other safeguards were in place in the city’s care home testing pilot, including the wearing of PPE and a ban on touching others.
“This has always been a pilot, not only to identify where the virus is in the city, but also to learn about different testing technologies and different testing strategies,” the spokesperson said. “The University of Liverpool and national public health agencies are working with us to evaluate how best to use the tests, and we are taking a careful approach with extra safeguards in place.”
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