NHS contact tracing app ‘is unlikely to reduce the spread of Covid-19’

The new NHS Test and Trace app won’t work unless the vast majority of the country installs it and even then social distancing will still be required, a new study claims.

The NHS app launched in the Isle of Wight last week as a pilot scheme, with users urged to scan barcodes when they go out to create a ‘virtual diary’ of movements.

This is the second trial on the island by NHS following its disastrous first attempt, which was abandoned in June.    

A new study by University College London found that these types of tracking apps only work if the vast majority of a population install and actively use them. 

By reviewing 15 earlier scientific studies into the use of the apps, the team found that even if 80 per cent of a population install them other public health restrictions would still be needed to slow the spread of the deadly virus. 

These measures include restrictions already in use to slow the spread including social distancing, wearing masks indoors and even closing pubs.

Researchers say that ‘automatic and semi-automated’ contact tracing apps are no substitute for human contact tracers calling people to tell them to stay indoors. 

The team from UCL say evidence on the effectiveness of automated contact tracing systems is limited and there is an ‘urgent need for further evaluation of these apps’. 

The original NHS app was supposed to have been launched across the country in mid-May following its trial period. 

But it was scrapped in June as it had a number of flaws and the government announced a dramatic U-turn as it ditched its self-made version in favour of the API built by tech giants Apple and Google. 

A trial of a revamped app has now started in the Isle of Wight and Newham in east London but officials can’t say if or when it will be rolled out more widely.

Even under optimistic assumptions – where up to 80 per cent of people are using a contract tracing app with 90 per cent of the identified contacts following quarantine advice – physically distancing and venue closures would still be required. 

Health Secretary Matt Hancock insists the app will ‘help keep the country safe’ but there are still concerns over high false positive rate – up to 45 per cent. 

Lead author Dr Isobel Braithwaite, of the UCL Institute of Health Informatics, said the studies painted a consistent picture that the automatic apps don’t work alone.

‘The systems will require large-scale uptake by the population and strict adherence to quarantine advice by contacts notified to have a significant impact on reducing transmission,’ Dr Braithwaite explained.

‘Although automated contact tracing shows some promise in helping reduce transmission of Covid-19 within communities, our research highlighted the urgent need for further evaluation of these apps within public health practice.’ 

The researchers looked at more than 4,000 studies on automated and partially-automated contact tracing and found 15 relevant research papers. 

Dr Robert Aldridge, of UCL, said there isn’t evidence about whether a notification from a smartphone would help break chains of transmission by giving advice to isolate due to contact with a case of Covid-19.

They say being given advice by a human public health contact tracer is more effective at encouraging people to stay indoors. 

‘We urgently need to study this evidence gap and examine how automated approaches can be integrated with existing contact tracing and disease control strategies, and generate evidence on whether these new digital approaches are cost-effective and equitable,’ Dr Aldridge explained.

The researchers said that if implemented effectively, contact tracing apps may offer benefits such as reducing reliance on human contact tracers, but it could also increase the risk of Covid-19 among vulnerable groups and raises privacy concerns.

Dr Braithwaite said: ‘We should be mindful that automated approaches raise potential privacy and ethics concerns, and also rely on high smartphone ownership, so they may be of very limited value in some countries.

‘Too much reliance on automated contact tracing apps may also increase the risk of Covid-19 for vulnerable and digitally-excluded groups such as older people and people experiencing homelessness.’

The findings have been published in the medical journal the Lancet. 

The landmark study will come as a hammer blow to the government’s hopes of creating a robust and effective track and trace system. 

Matt Hancock had initially promised the NHS would build its own app which would work alongside human contact tracers. 

It was based on a centralised model which funnelled all the data from handsets to a central server in NHS headquarters. 

This was in direct contradiction to the approach taken by Apple and Google, who teamed up in a rare partnership to create a framework which country’s could use to build their own app. 

The two tech behemoths focused on a decentralised approach where there was no data being shared between devices and severs, helping to preserve privacy of users.

Also, the two companies are responsible for by far and away the two most popular mobile operating systems in the guise of iOS and Android. 

Being aware of all the security features and protocols that may make interaction between the different phones, they were able to devise a system that worked. 

NHS however, announced in April it would press on regardless of these inevitable issues and failed spectacularly.  

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. The app was abandoned a month after launch. 

In that time, Google and Apple released their software for free and it was picked up by 22 countries on the day it was released, on May 20. 

Perhaps unsurprisingly, trials revealed the Apple and Google technology can spot 99 per cent of close contacts using any type of smartphone — but it cannot currently tell how far away they are, officials claimed today. 

It took the UK until June 18 to admit this publicly and switch to the Google-Apple  model. 

Officials refused to reveal how much money has been spent on the now-scrapped app. 

The model, based on the Apple-Google system, uses, on average, two to three per cent of a phone’s battery life each day, officials say. 

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.’