The government’s beleaguered Covid-19 NHS app hit the headlines again recently after the Sunday Times revealed exclusively that it failed to send alerts to thousands of people to tell them to self-isolate after coming into contact with infected people.

The failure of the app – which has been downloaded enthusiastically by 19 million users – was attributed to the Department of Health and Social Care setting the software to the wrong sensitivity level.

This story was of particular interest to researchers at The Business School (formerly Cass), City, University of London.

This past April, as central government, local authorities and public health officials scrambled to understand the best way to encourage the public to adopt a contract tracing app, the researchers discovered that it is possible to implement a privacy-respecting app that can be widely adopted, but only if the NHS, rather than the government, run it.

The researchers also found that adoption rates increase further if the app is linked to priority testing for Covid-19 for those who get infection alerts.

The researchers asked a representative sample of 2061 UK adults to choose between different contact tracing app configurations to estimate their preference for various features. This information was used to simulate the adoption rates for different potential contact tracing apps.

“When we did the study, the world was different and the app wasn’t ready yet,” said Professor Caroline Wiertz, a co-author of the study. “Given that people have now heard so much about it or might have used it themselves, if we did the research again, we might find completely different results.”

The key findings of the research were:

• A ‘Maximum Adoption’ app that would reach the highest adoption, regardless of implications for privacy and civil liberties, has the maximum adoption rate of 77.6 per cent.

• A ‘Recommended’ app that would reach the highest adoption while safeguarding privacy and civil liberties has an adoption rate of 73.5 per cent.

• An ‘Expected NHSX’ app that the NHSX/UK government have announced (based on an interpretation of press coverage and NHSX blogs) has the lowest adoption rate with 51.1 per cent.

Based on their simulations, the researchers recommended a contact tracing app that strikes a balance between maximising adoption while safeguarding privacy and civil liberties with the following features:

1. Oversight of the app by the NHS
2. Priority access to testing for people using the app and in self-isolation
3. Not used to monitor or enforce self-isolation
4. Voluntary use of the app
5. Data only stored for 14 days
6. Voluntary reporting of test results
7. Anonymous contact tracing
8. Does not upload location data
9. Alerts for confirmed and suspected infections
10. Works internationally

Although there have been clear concerns raised about the government’s app, Professor Wiertz remains hopeful that it can still play a significant part in the fight against the pandemic, in conjunction with a successful testing system.

“I think what is still important now is getting access to efficient testing. That was the second most important driver in our study and we can see now that not having an efficient, working testing system in place is a real risk”.

Read Predicted Adoption Rates of Contact Tracing App Configurations here. The authors are Professor Caroline Wiertz, Dr Aneesh Banerjee, Dr Oguz A. Acar and Adi Ghosh, The Business School, City, University of London.

Amy is City’s PR and Communications Manager. She and the team of Senior Communications Officers are responsible for promoting the University’s five Schools in the national and international media. Amy trained as a journalist at the University of Technology Sydney and has freelanced for the Sydney Morning Herald, the Daily Telegraph and the BBC World Service. She has also worked as a press officer, editor and copywriter for universities and museums in Australia.