The UK government is urging everyone in England to take a free Covid-19 lateral flow test (LFT) twice a week.
The public is being encouraged to “get into the habit” of using LFTs twice a week, with a major information campaign launching across TV, radio, press, digital, out-of-home advertising and social media.
The tests will be available in pharmacies, workplaces and community spaces, and can also be ordered for home delivery.
Health and Social Care Secretary Matt Hancock said: “Alongside the successful roll-out of the vaccination programme, rapid testing will be one of our most effective weapons in tackling this virus and ensuring we can cautiously reopen our economy and parts of society that we have all missed.”
Research published in January in the Annals of Internal Medicine suggests that around a third of people infected with Covid-19 are asymptomatic, meaning regular mass testing could theoretically help pick up these ‘missing’ cases.
Medicine Direct clinical director and superintendent pharmacist Hussain Abdeh told Medical Device Network: “LFTs are highly effective at identifying people with a high viral load, meaning that they are much more infectious than others. The LFT rollout is essential for England and the UK in reopening the economy given the speed at which a positive infectious result is given, in just 30 minutes.
“LFTs are typically not as accurate as PCR tests which are usually carried out under supervision and sent to a lab for testing. Inaccuracies on positive and negative results [represent] one of the biggest risks that LFTs possess.”
Statistics on LFT accuracy have varied wildly throughout the pandemic, especially in asymptomatic people.
The UK government said analysis by NHS Test and Trace shows that for every 1,000 LFTs carried out there is fewer than one false positive
But a review of 64 studies from Europe and the US into LFT accuracy showed a wide variance between different brands, and were far better at identifying Covid-19 infection in people with symptoms than those without them.
LFT sensitivity in symptomatic people ranged from 34% to 88%, with an average accuracy of 72%.
In people without symptoms the LFTs correctly identified an average of 58% of those who were infected.
The Innova test being used in the UK demonstrated a sensitivity of 58% in people with symptomatic Covid-19, but the performance of the device in asymptomatic people was not included in the analysis as robust studies on this have yet to be published.
The limited pilot data available suggests an asymptomatic sensitivity of around 40%.
University of Birmingham professor of biostatistics Jon Deeks, who led the research, told Medical Device Network: “Government evidence of how well [Innova] test detects the virus in people without symptoms is based on only 70 cases in Liverpool, where the test only found 28 (four out of 10) and even missed one in three with high viral loads. These tests were undertaken in a testing centre with trained staff – we have no evidence how well the test will work in untrained hands in people’s homes.
“False negatives may lead people to unwittingly spread the infection, and false positives will lead individuals and their families to unnecessarily isolate. The possibilities of these harms need to be considered against the small numbers of cases that testing will identify. This testing may not be cost-effective or do more benefit than harm. These questions clearly should have been answered before national roll-out.”