As isolation rules for those who have had two coronavirus vaccinations were relaxed on Monday, it emerged that users were not told that the app could notify individuals that they had been in contact with an infected person up to five days prior to a positive test.
Official guidance defined close contact as occurring two days before the person developed symptoms and NHS Test and Trace uses two days.
The app, however, was “pinging” people who had been in contact with an infected individual up to five days before they became ill with Covid symptoms, a Whitehall source told The Guardian.
According to the report, the error was flagged to former health secretary Matt Hancock, shortly before he resigned, but has never been publicly acknowledged.
It was later announced, by new health secretary Sajid Javid, that the app would be updated to make it less sensitive with people without symptoms only having their contacts searched for the two days prior to a positive Covid test, rather than five.
At the time, Mr Javid said: “We want to reduce the disruption that self-isolation can cause for people and businesses, while ensuring we’re protecting those most at risk from this virus.”
He added: “This update to the app will help ensure that we are striking the right balance.”
It is understood that online guidance from the Department of Health and Social Care (DHSC) had in fact never suggested a five day contact period prior to symptoms developing.
This news means that thousands of people were potentially instructed to self-isolate when they did not need to.
Shadow health minister Justin Madder said that the situation was “shambolic”. “The Covid app has been one mess after another and a lack of clear information and guidance around the app only undermines its effectiveness,” he said.
At the peak of the so-called “pingdemic” around half a million people were being asked to isolate by the NHS Covid app and Test and Trace every week. This caused widespread staff shortages with concerns that areas of the economy were at risk of shutting down.
Since then, the Covid app’s sensitivity has been altered.
When asked for a response to the allegations of an error in the NHS app and a lack of transparency about the five say isolation period, a DHSC spokesperson told The Independent: “The NHS Covid-19 App is a key tool in our pandemic response, saving thousands of lives and breaking chains of transmission. The app prevented up to 2,000 cases of Covid-19 a day in July.
“App users will only ever be advised to isolate if they have been in close contact with an individual who goes on to test positive for Covid-19. It is important users isolate when asked to do so in order to stop the spread of the virus.
“The recent change to the app logic will result in fewer low-risk contacts being advised to isolate, while advising the same number of high-risk contacts to self-isolate.”
Meanwhile, on Monday the government relaxed the isolation rules so that those who have been double vaccinated now no longer need to stay at home for 10 days if they have been in close contact with a confirmed Covid case.