The NHS contact tracing app is telling 150,000 people a week to self-isolate as the reopening of pubs and restaurants motivates more people to use it.
Despite reports that people who have had two vaccine doses are deleting the app, use has increased because of the requirement to “check in” at food and drinks venues by using a phone to scan a QR code linked to the app.
After its use declined during the winter lockdown, a third wave of cases, predominantly among young people, has led to a surge in alerts in recent weeks. In the week to June 16, 150,485 people were “pinged”, up from 46,972 two weeks earlier and 5,565 in mid-April.
The app sent alerts about potential outbreaks at 467 venues last week, a twentyfold increase in three weeks. However, this was still a relatively small proportion of the 12.4 million check-ins logged by the app each week.
People who have been to venues that have been linked to more than two cases in 24 hours are sent warning alerts. If there have been more than four cases, they are advised to get tested. Only if the app shows they have been near someone with a case of the virus are they told to isolate for ten days.
Professor Christophe Fraser, leader of the contact tracing app programme at Oxford University and a senior scientific adviser to the NHS, said use of the technology had “accelerated” since hospitality reopened and insisted that it was helping to blunt the present wave.
Matt Hancock, the health secretary, has been a strong advocate of the technology, which uses smartphones’ Bluetooth capability to detect when a user has been in close contact with someone who has told the app they have tested positive, sending automated alerts much more quickly than human contact tracers.
However, critics have questioned the reliability and effectiveness of the app, particularly given that ministers scrapped plans for a home-grown version and rely on Google and Apple technology, which limits the amount that is known about users. Nonetheless NHS data figures show the app has been downloaded 25.5 million times, with 286,753 people starting to use it last week.
However, two MPs who have been fully vaccinated — one Labour and one Tory — told The Times they had turned off the Bluetooth function to avoid the risk of being ordered to self-isolate. One of them said: “I’m double jabbed, so why do we still have to self-isolate? What’s the point in vaccinations if we don’t get any benefits from it?”
Fraser said these examples were not typical. He added: “If you look at the epidemic now it is more concentrated among young people and young people are more likely to use the app. Right now the app is preventing a lot of transmission among the younger population and the impact right now is the highest it has been since December.”
Because the app is anonymous the NHS does not know if people asked to isolate are doing so but Fraser said surveys showed people reduced contacts by about 60-80 per cent after a ping.