NHS COVID app prevented 'thousands' of deaths, says report

New peer-reviewed research has backed claims the NHS COVID app did indeed prevent thousands of deaths and hundreds of thousands of infections.

From BBC News:

The NHS contact-tracing app had a significant impact on lowering the spread of the coronavirus in the UK, a peer-reviewed paper has found.

Researchers estimate the app prevented hundreds of thousands of cases of the disease, and thousands of deaths.

"On average, each confirmed case who consented to notification of their contacts through the app prevented one new case," the paper claims.

The paper says that from September 24 through the end of 2020 saw the app "used regularly" by 16.5 million people, 28% of the population. 1.7 million exposure notifications were sent following 560,000 users lodging positive tests. The paper estimates that for every 1% increase in app use, cases were reduced by between 0.8% and 2.3%.

The disparity in percentages is down to different calculation methods, the first is modeling based on transmission rates and rule compliance, the second is based on data from local authorities:

Researchers said the number of cases prevented was 284,000 on the modeling approach, and 594,000 using the statistical one. That translated to 4,200 or 8,700 prevented deaths respectively.

"On balance, an effect size between the two estimates seems most likely," the researchers said.

The research claims that the app may have also had the added effect of making more people mindful of social distancing, knowing that there was an app monitoring their distance that might advise them to quarantine at a later date.

Estimates in February suggested the app could have prevented up to 600,000 infections. The app was built on Apple and Google's exposure notification API.