The Government Has Denied It Is Planning To Reduce Rapid Covid Testing Following Concerns Over False Positives
People in England have been encouraged to order the NHS kits to take twice-weekly tests (Alamy)
The Government has batted away suggestions it could scale back the rapid testing programme despite internal concerns over false positive rates.
The Department of Health has defended the "essential tool" for catching asymptomatic cases, despite leaked emails showing growing concern that between just 2% to 10% of positive results may be accurate in places with low infection rates.
It comes after the launch of a new scheme which allows anyone in England to order packs of the rapid lateral flow devices (LFD) to their homes as part of the plans for mass-testing as lockdown measures are lifted.
The test, which can be taken at home, provide a result within 30 minutes, with those getting a positive result expected to self-isolate and book themselves in to get a more accurate PCR test to confirm the infection.
Ministers have spent billions on purchasing the devices which will form a key part of the government's trial programme for Covid status certification to allow people to prove they have recently been tested for the virus.
But in emails seen by the Guardian, senior officials in Health Secretary Matt Hancock's department have raised concerns about the accuracy of the tests, especially in areas such as London, with low infection rates.
In one email, Ben Dyson, an executive director of strategy at the health department, said there was a "fairly urgent need for decisions" on "the point at which we stop offering asymptomatic testing".
In a message on 9 April, the day people were first able to order the kits, he wrote: "As of today, someone who gets a positive LFD result in (say) London has at best a 25% chance of it being a true positive, but if it is a self-reported test potentially as low as 10% (on an optimistic assumption about specificity) or as low as 2% (on a more pessimistic assumption)."
Meanwhile, the paper reports that Professor John Simpson, head of PHE's public health advice, guidance and expertise, had raised concerns about the testing programme before the scheme was launched.
He wrote: "We are a little concerned that this proposal does not provide the evidence needed to justify the extension of testing in the way proposed, does not consider alternative approaches to achieving the over-arching aim (of reducing community transmission) and does not provide a framework for evaluation that would make it possible to determine if the approach actually achieves what it intends."
But a Department for Health spokesperson defended the programme, saying the false positive rate was fewer that one in 1,000.
"With around one in three people not showing symptoms of Covid-19, regular, rapid testing is an essential tool to control the spread of the virus as restrictions ease by picking up cases that would not otherwise have been detected," a spokesperson said.
"Rapid testing detects cases quickly, meaning positive cases can isolate immediately, and figures show that for every 1,000 later flow tests carried out, there is fewer than one false positive result."