Digital contact tracing apps: do they actually work? A review of early evidence

Throughout the COVID-19 pandemic, many smartphone apps were launched to complement and augment manual contact tracing efforts without a priori knowledge of their actual effectiveness. A year later, do we know if they worked as intended? An analysis of early evidence—from both the literature and actual usage—by AlgorithmWatch finds that results, so far, are contradictory and that comparability issues might prevent an informed, overall judgment on the role of digital contact tracing apps in response to the COVID-19 pandemic altogether.