New study says NHS contact tracing app was very effective

A new peer-reviewed study that has appeared in the scientific journal, Nature, suggests that the NHS contact tracing app that was used in England and Wales was very effective. It said that 16.5 million people used the app and that 1.7 million exposure notifications were sent to users

The researchers predicted that 6% of app-notified people showed symptoms and tested positive for the virus and that for each notification sent to contacts, one case of the coronavirus was averted. They also said that for every percentage point increase in the number of users, cases could be reduced by 0.8% and 2.3% depending on which approach you use to estimate the figure.

Discussing how it estimated the number of cases averted, the researchers wrote:

“We estimated the number of cases averted by the app using two complementary approaches. Modelling based on the notifications and SAR gave 284,000 (108,000-450,000), and statistical comparison of matched neighbouring local authorities gave 594,000 (317,000-914,000).”

The academics involved in the study said that the findings give us evidence that the continued development and deployment of such apps would be beneficial, especially in populations that are still awaiting a vaccination.