The NHS Test and Trace smartphone app is being re-launched today with a second round of trials on the Isle of Wight and in the London borough of Newham.
England’s beleaguered app, of which the first version had to be scrapped in June, has now been recreated using technology made by Google and Apple.
Officials are rolling out tests to some staff in the NHS and residents of the two areas to test whether it is good enough to use nationwide.
If the app is found to work it will be used alongside the human contact-tracing system which is based on call centres and local councils visiting people’s homes.
Bluetooth technology will keep a record of which phones spend 15 minutes within 2metres (6’7″) of one another and then alert people if they have been near someone who later tests positive for Covid-19.
Users will also have an ‘isolation companion’ which has countdown timer if someone has to self-isolate, and will be able to ‘check in’ to places they visit using QR codes.
They will also be shown what the risk level is in their local area based on the first half of their postcode, with places being categorised as low, medium or high risk.
The app will rely totally on members of the public co-operating, volunteering to let it track their connections and following the instructions it gives them on getting tested and self-isolating.
Despite efforts to iron out flaws in the technology, the Department of Health has admitted that around half of people who are warned they have been near an infected person will actually not have been within the 2m for 15 minutes danger window.
And three out of 10 people who were put at risk – 31 per cent – won’t receive a notification at all.
The announcement of developments in the app comes as data on the manual contact tracing today revealed that test results are getting slower again.
Statistics showed this morning that around two-thirds of people who got swab tests (67.4 per cent) received their result within 24 hours, down from 76.9 per cent last week. Prime Minister Boris Johnson had promised to have this figure at 100 per cent last month.
The newest version of the app is being launched after the first attempt was abandoned in June because it did not work on Android smartphones.
The NHS’s app — which was originally promised for mid-May and the NHS spent months developing — was unable to spot 25 per cent of nearby Android users and a staggering 96 per cent of iPhones in the Isle of Wight trial.
This was because the Bluetooth system developed by the NHS effectively went into ‘sleep mode’ when the phone screens were locked and developers couldn’t fix the glitch.
Different Bluetooth technology made by the phone manufacturers Apple and Google themselves has turned out to be significantly better at detecting other phones.
Officials said the app software now reliably detects 99.3 per cent of nearby app users, regardless of what type of phone they have.
Another major difference between the two is that Apple and Google’s technology stores the anonymously log of someone’s contacts entirely in the phone – it is never shared with anyone else and can be deleted at any time – whereas the NHS’s worked on a system which meant it had to be sent to a centralised database.
Officials have changed this to squash concerns about privacy, now insisting the app ‘tracks the virus, not people’.
Once hailed as a vital part of the contact tracing system, the app is now an addition to the human system, officials say.
Dido Harding, the chair of NHS Test and Trace, said: ‘There is no silver bullet when it comes to tackling coronavirus.
‘The app is a great step forward and will complement all of the work we are doing with local areas across the country to reach more people in their communities and work towards our vision of helping more people get back to the most normal life possible at the lowest risk.
‘I am hugely grateful to the Isle of Wight, Newham and the NHS responders for playing their part.’
Newham was chosen for the mainland trial because it is such a diverse and busy area, Baroness Harding said.
The London borough has high levels of deprivation and is extremely diverse – white British people make up only 17 per cent of the population and there is no ethnic majority.
It is also very densely populated, home to around 352,000 people, and therefore a ideal for testing the app in a city environment where the risk of infection is higher.
People who use the app will be asked to put in the first half of their postcode so they can be given the risk level for their local area, which will be low, medium or high.
This section will then have links to more information about specific rules if that area has a stricter lockdown than other parts of the country.
The announcement that the app will re-enter trials comes as data shows the NHS Test & Trace system is still struggling.
A total of 52,735 people who tested positive for Covid-19 in England have had their cases transferred to the NHS Test and Trace contact tracing system since its launch, according to figures from the Department of Health and Social Care.
Of this total, 41,254 people (78.2 per cent) were reached and asked to provide details of recent close contacts, while 9,938 (18.8 per cent) were not reached.
A further 1,543 people (2.9 per cent) could not be reached because their communication details had not been provided.
The figures cover the period from May 28 to August 5.
The NHS Test and Trace figures also show that, for cases handled by local health protection teams, 97.9% of close contacts of people who tested positive for Covid-19 have been reached and asked to self-isolate.
By contrast, for those cases handled either online or by call centres, 56.7% of close contacts have been reached and asked to self-isolate.
Those figures cover the whole 10-week period of Test and Trace.