Coronavirus: Test and trace app unlikely to succeed without widespread public support, research suggests

Scientists say physical distancing would still be needed even with contact tracing apps

The government’s contact tracing app is unlikely to be effective in reducing the spread of coronavirus unless it receives widespread support from the public, research has suggested.

A team of scientists, led by University College London, found such apps would need large-scale uptake by the population and support from other public health control measures to be successful.

The findings, published in the journal Lancet Digital Health, were based on a review of data from 15 scientific studies published between January and mid-April this year.

The researchers added that evidence on the effectiveness of automated contact tracing systems was limited and there was an “urgent need for further evaluation” of such apps.

Under optimistic assumptions, where up to 80 per cent of smartphone owners in the UK used a contact tracing app and more than 90 per cent of identified contacts followed quarantine advice, other public health control measures would still be needed to control the number of infections, the researchers said.

These measures would include restrictions, such as physical distancing and the closure of indoor spaces, which are already in place in many countries.

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

However, most of these studies were either based on modelling, or were observational or case studies, or did not include the full information needed to assess the effectiveness of contact tracing apps.

“We currently do not have good evidence about whether a notification from a smartphone app is as effective in breaking chains of transmission by giving advice to isolate due to contact with a case of Covid-19 when compared to advice provided by a public health contact tracer,” Dr Robert Aldridge, of UCL Institute of Health Informatics, said.

“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.”

A public trial of England’s revamped Covid-19 contact tracing app began last week in the Isle of Wight and the London Borough of Newham, with an additional group of NHS volunteer responders.

It came after the government ditched its plans to develop a custom-made app and switched to technology provided by Apple and Google in June.

Officials admitted that the app they had created was highly inaccurate and picked up just 4 per cent of contacts on Apple phones and 75 per cent of contacts on Android handsets.

Meanwhile, Apple and Google’s model picked up 99 per cent of contacts on both Android devices and iPhones.

The trial also came after the announcement of a major shake-up of the government’s manual contact tracing system this month which will give local authorities more power to track infections in their area.

The Department of Health and Social Care said it would cut the number of national contact tracers from 18,000 to 12,000 by 24 August, with NHS Test and Trace employees set to be redeployed locally.

Additional reporting by PA