Matt Hancock launches contact-tracing app with Isle of Wight trial

A new contact-tracing app for managing the coronavirus outbreak will be piloted on the Isle of Wight this week, the health secretary has confirmed, despite concerns its centralised setup carries privacy risks and will reduce uptake.

Matt Hancock said there had been “huge enthusiasm” on the island off the south coast of England for the idea of trying out the new app, which will alert users if they have been close to someone with the Covid-19 virus.

Having stopped trying to track every case back in March, when the virus began spreading freely in the population, the government is now recruiting what the health secretary called an “army” of human contact tracers. These will work alongside the new app, in a bid to establish how and where the disease is spreading.

Related: 'Guinea pigs': Isle of Wight residents' give mixed welcome to contact tracing app

Users who experience symptoms will be asked to notify the app and will then be offered a test. Access to the app will initially be offered to NHS staff on the island, with members of the public receiving a letter on Thursday urging them to download the app and join the trial.

Questions have been raised about the app’s effectiveness. A report in the Health Service Journal on Monday – flatly denied by the government as “factually untrue” – quoted sources that claimed it was not fit for inclusion in the NHS’s own app library, had not passed basic cybersecurity tests and was still “wobbly”. It also said there were concerns about how users’ privacy would be protected once they logged symptoms and became traceable.

The NHS’s decision to take a centralised approach has also been criticised. Alan Davidson and Marshall Erwin of the not-for-profit internet organisation Mozilla said: “The biggest problem … is that it would expand government access to the ‘social graph’ – data about you, your relationships, and your links with others.

“Regardless of the particulars, we know this social graph data is near impossible to truly anonymise. It will provide information about you that is highly sensitive, and can easily be abused for a host of unintended purposes.”

Apple and Google proposed a decentralised alternative, in which the contact tracing would happen on individual phones, rather than on the NHS’s servers, and which would allow them to sign up the vast numbers of users it needs.

But Matthew Gould, chief executive of the NHS’s digital arm, defended the decision to go for a centralised app, telling parliament’s joint committee on human rights on Monday: “Even if the take-up rate is 20%, that gives us important insights into how the virus is spreading. At 40 or 50% it will make a big difference.”

Hancock gave further details on the app at Monday’s daily Downing Street press conference, where he also confirmed that the total reported number of deaths from Covid-19 was now 28,734 – an increase of 288.

The health secretary called the creation of a contact-tracing system a “huge national undertaking of unprecedented scale and complexity”. He said he expected to have the system in place by the middle of this month.

Hancock had previously said 18,000 contact tracers might be needed – but he said he would adjust that figure if a new survey showed the virus was more prevalent than previously thought. The Office for National Statistics is carrying out a large-scale survey in a bid to create a clearer picture about how many people have contracted the virus.

Hancock was accompanied by the deputy chief medical officer for England Jonathan Van-Tam, who gave an update on the government’s five tests for lifting the lockdown, which has now been in place for six weeks.

He said that while the data showed the government was in a good position on passing the first test, a sustained fall in daily deaths, there was still a deep scientific discussion going on about the fifth test concerning avoiding a second peak.

He added that the government wanted to see the number of new Covid-19 cases falling before it considered it safe to lift the restrictions. “New cases need to come down further,” he said.