Self-testing for the coronavirus may soon become the norm in the UK, as part of plans announced to facilitate the exit from the lockdown.
All adults will be encouraged to test themselves for the virus twice a week, reports the Times, with an ad campaign urging people to “play their part” by regularly making sure that they are not contagious. Such tests, called lateral flow tests, can give a result in 30 minutes and do not need to be sent to a lab to get the results, unlike the PCR tests used by the NHS for symptomatic cases.
Children, teachers and adults in households with children and young people can already access free rapid tests if they do not show symptoms of the virus. While those showing symptoms are advised to book for a swab PCR test via the NHS.
Companies have also been encouraged to show interest in the government’s free workplace testing program – which, again, would use lateral flow testing. So far, 48,000 companies have registered.
Two UK companies have signed agreements with the Department of Health and Social Affairs (DHSC) to perform lateral flow testing and will aim to perform two million rapid rotation tests each week by the end of May, PA Media reports. The hope is that the tests will detect asymptomatic cases, which are believed to be prevalent in one in three people, and force people to stay home if they test positive.
HuffPost UK asked DHSC if adults would be required to test themselves for Covid twice a week. They have neither confirmed nor denied that this would be the case.
The advantages of testing us
It takes about 4 to 5 days for a person infected with the virus to infect another person, which means that contact tracing needs to identify and reach contacts as soon as possible. But many people don’t get tested for at least 24 to 48 hours after symptoms develop, and PCR tests can take more than 48 hours to return results. This leaves quite a space for transmission to occur.
The goal of rapid testing is to uncover virus cases in the community and break any chain of transmission, stopping outbreaks before they happen and catching cases much faster. They can fill gaps in test access and ease the pressure on laboratories analyzing PCR test results.
Dr Alexander Edwards, associate professor of biomedical technology at the University of Reading, tells HuffPost UK that if cases can be detected early in the community, it may be possible to block transmission and spread, provided the Positive tests are fully supported in self-isolating and followed up for sequencing to track variants.
Rapid tests are not designed to work on their own, but to be implemented alongside other measures such as social distancing, wearing face masks, hand hygiene, vaccination and PCR testing for people. showing symptoms.
The challenges of the self-test
The accuracy of rapid flow tests has been questioned. The first trials of lateral flow tests revealed different results. Research from Public Health England’s Porton Down lab and the University of Oxford found that testing was more accurate when done by lab scientists (picking up 79% of positive cases). When healthcare workers took the tests, the accuracy dropped to 73%. And when done by self-educated audience members, that percentage dropped to 58%.
Real-world data suggests that figure could be even lower. Pilot data from Liverpool, which tested city-wide lateral flow tests, found they detected 48.89% of Covid-19 infections in asymptomatic people compared to a PCR test on swab sent to a laboratory.
To perform the tests at home, you rely on untrained people to perform their own tests, which can adversely affect the results. The World Health Organization (WHO) recommend performing rapid tests by trained operators. “Home testing requires extremely clear instructions and more guidance should be provided to make it as simple as possible without reducing accuracy,” says Dr Edwards.
“Home tests require extremely clear instructions”
– Dr Alexander Edwards, Associate Professor of Biomedical Technology at the University of Reading
A big challenge is that most manufacturers make products specifically for use by trained professionals, he says. “Home tests should be fully evaluated at home before they are deployed. We should also study the effectiveness of regular testing in reducing transmission, otherwise we will never know how well it works. ”
Dr Angela Raffle, Honorary Lecturer in the Department of Population Health Sciences at Bristol University School of Medicine, says the announced twice-weekly self-test plan appears to be “much more on the line. creation of a market for home testing, only on pandemic control ”.
We need “transparent analyzes” from the NHS Test & Trace on the adoption and false positive results of lateral flow tests of secondary school students in England in early March, said Professor Sheila Bird, formerly responsible for the program at the school. MRC Biostatistics. Unit at the University of Cambridge. We require that ” [a] better testing, better design, better analysis feedback, better adoption, ”she adds. “England deserves better.”
If rapid tests give false positive results, that means people who do not have Covid would be asked to self-isolate unnecessarily. Likewise, there is also concern that such tests will report false negative results – when people are told they don’t have Covid but do have it, and they come out, to spread it further.
Dr Raffle is nodding at the lack of evidence demonstrating the impact of rapid tests so far. “They haven’t done these studies, and they’re deploying them as part of their ‘Moonshot’ project, against Sage’s advice,” she says.
“There is a good chance that the least risky will be those who pass the tests, and it opens a Pandora’s box if testing becomes mandatory, especially if the isolation results from a self-test of questionable reliability. ”