The UK could potentially have another success story on its hands during the grim Coronavirus pandemic, after a research paper said the NHS Covid-19 app had helped saved thousands of lives.
The development of the app by NHSX, the Department of Health’s NHS technology division, was not without a struggle, but when it did arrive it helped play an important part in limited the spread of Covid-19 during the latter half of 2020, the paper suggests.
Right from the start of its development, there were concerns about privacy, which caused some delays.
People in England and Wales were the last to get a contract tracing app in September 2020.
Development had been delayed after the NHS had switched to the Exposure Notifications platform in June 2020, after finding that its initial, independent system missed too many instances where virus transmission could have occurred.
It instead opted for the system from Apple and Google.
Apps using Apple and Google’s Exposure Notifications platform are barred from sending precise location data to public health authorities, or to the two tech companies.
The contact tracing element of the NHS Covid-19 app essentially worked by using Bluetooth to log the amount of time a person spend near other app users, and the distance between the user and the other person, so it can alert the user telling them to self-isolate, if someone they had been close to (on public transport or in the supermarket for example) later tested positive for Covid-19.
It also allowed users to scan QR codes of locations (i.e. food takeaways, supermarket etc) in order to maintain a log of locations the user had visited. This could be used to alert the user if one of the locations became a virus hotspot.
And this contact tracing element, a research paper has suggested, prevented hundreds of thousands of cases of Coronavirus, and hence saved thousands of deaths, the BBC reported.
“On average, each confirmed case who consented to notification of their contacts through the app prevented one new case,” the paper reportedly claims.
The research paper published in Nature for peer review, and it examined the app’s peformance over a three month period.
“Here we investigated the impact of the NHS COVID-19 app for England and Wales, from its launch on 24 September 2020 through to the end of December 2020,” said the researchers. “It was used regularly by approximately 16.5 million users (28 percent of the total population), and sent approximately 1.7 million exposure notifications,” after 560,000 app users tested positive.
The BBC reported that the researchers estimate that every 1 percent increase in app users resulted in cases being reduced by between 0.8 and 2.3 percent.
The difference between those two numbers comes down to two different ways the team used to calculate the impact of the app.
The first used a ‘modelling’ approach, making assumptions about transmission and how strictly people stuck to quarantine.
The second involved looking at data from local authorities on actual cases.
Both were compared to how widely the app was used to estimate its impact.
Researchers were quoted by the BBC as saying the number of cases prevented was 284,000 on the modelling approach, and 594,000 using the statistical one.
That translated to 4,200 or 8,700 prevented deaths respectively, which is a notable achievement for the NHS app.
“On balance, an effect size between the two estimates seems most likely,” the researchers said.
Last month Apple and Google blocked an update to the NHS’ Covid-19 contact tracing app over a violation of their privacy rules.