Researchers: ‘App Is Having a Positive Effect on Reducing the Impact of the Virus’ Researchers: For every 1% increase in app users, the number of infections can be reduced by 0.8% or 2.3%. They estimate the app has helped avert between 224,000 and 914,000 new infections in England and Wales from October to December 2020. The contract-tracing apps being used in the U.K. run on newer Apple and Android devices and use Bluetooth to help detect other devices within range.”]