Self-testing for coronavirus could soon become the norm in the UK, under reported plans to ease out of lockdown.
All adults will be encouraged to test themselves for the virus twice a week, the Times reports, with an advertising campaign urging people to “play their part” by regularly ensuring they are not infectious. Such tests, known as lateral flow tests, can give a result in 30 minutes and don’t need to be sent to a laboratory for results, while the PCR tests used by the NHS for symptomatic cases do.
Children, teachers and adults in households with children and young people can already access free rapid testing if they don’t have symptoms of the virus. While those with symptoms are urged to book in for a PCR swab test via the NHS.
Businesses have also been encouraged to register interest for the government’s free workplace testing programme – which again, would use lateral flow tests. So far, 48,000 companies have signed up.
Two British firms have signed deals with the Department of Health and Social Care (DHSC) to make lateral flow tests and will be aiming to make two million rapid turnaround tests every week by the end of May, reports PA Media. The hope is the tests will detect asymptomatic cases, thought to be prevalent in one in three people, and require people to stay home if they test positive.
HuffPost UK asked DHSC whether adults will be required to test themselves for Covid twice a week. They did not confirm or deny this would be the case.
The benefits of testing ourselves
It takes roughly 4-5 days for someone infected with the virus to infect another person, which means contact tracing must identify and reach contacts as soon as possible. But many people don’t get a test until at least 24-48 hours after developing symptoms and PCR tests can take more than 48 hours to return results. This leaves quite the gap for transmission to occur.
The aim of rapid testing is to uncover cases of the virus in the community and break any chains of transmission, stopping outbreaks before they occur and picking up cases much quicker. They can fill gaps in access to testing and alleviate pressure on the laboratories analysing PCR test results.
Dr Alexander Edwards, associate professor in biomedical technology at the University of Reading, tells HuffPost UK if cases can be picked up early in the community, it might be possible to block further transmission and spread, as long as those testing positive are supported fully in self-isolating and followed up for sequencing to track variants.
Rapid tests are designed not to work alone, but to be implemented alongside other measures like social distancing, wearing face masks, hand hygiene, vaccination, and PCR tests for those with symptoms.
The challenges of self-testing
The accuracy of rapid flow tests has been called into question. Initial trials of lateral flow testing have unearthed different outcomes. Research from Public Health England’s Porton Down laboratory and the University of Oxford found the tests were most accurate when carried out by lab scientists (picking up 79% of positive cases). When healthcare workers did the tests, the accuracy dropped to 73%. And when carried out by self-trained members of the public, this fell to 58%.
Real world data suggests this figure might be even lower. Pilot data from Liverpool, which trialled the lateral flow tests on a city-wide basis, revealed they detected 48.89% of Covid-19 infections in asymptomatic people when compared with a PCR swab test that was sent off to a lab.
To carry out the tests at home, you’re relying on people without training to conduct their own tests, which might hinder results. The World Health Organisation (WHO) recommends rapid tests should be conducted 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 testing requires extremely clear instructionsDr Alexander Edwards, associate professor in biomedical technology at the University of Reading
A big challenge is that most manufacturers produce products specifically for use by trained professionals, he says. “Home tests must be fully evaluated in the home before rollout. We should also study how effective regular testing is at reducing transmission, otherwise we’ll never know how well it works.”
Dr Angela Raffle, honorary senior lecturer at the University of Bristol’s Medical School Dept of Population Health Sciences, says the reported plan for twice weekly self-testing seems to be “far more about creating a market for home tests, than it is about controlling the pandemic”.
We need “transparent analyses” from NHS Test & Trace about the uptake of, and false-positive results from, the lateral flow testing of secondary pupils in England at the start of March, said Professor Sheila Bird, formerly programme leader of the MRC Biostatistics Unit at the University of Cambridge. We require “[a] better test, better design, better analysis feedback, better uptake,” she adds. “England deserves better.”
If the rapid tests cause false positive results, it means people who are not sick with Covid would be asked to self-isolate unnecessarily. Likewise, there is also concern such tests could flag up false negative results – where people are told they don’t have Covid but they do, and they go out, only to spread it more.
Dr Raffle nods towards the lack of evidence demonstrating the impact of rapid tests so far. “They haven’t done these studies, and they are rolling this out as part of their ‘Moonshot’ project, against advice from Sage,” she says.
“The chances are that those least at risk will be the ones who take the tests, and it opens a Pandora’s box if testing moves to being mandatory, especially if isolation is consequent on a self-test of questionable reliability.”
