The Dilemma of contacttracing apps: Can this crucial technology be both effective and private?

Abstract

IN JUNE, as the coronavirus swept across the United States, Paloma Beamer spent hours each day helping her university plan for a September reopening. Beamer, an associate professor of public health at the University of Arizona, was helping to test a mobile app that would notify users if they crossed paths with confirmed COVID-19 patients. • A number of such 'contact tracing' apps have recently had their trials by fire, and many of the developers readily admit that the technology has not yet proven that it can slow the spread of the virus. But that caveat has not stopped national governments and local communities from using the apps. • 'Right now, in Arizona, we're in the full-blown pandemic phase,' Beamer said, speaking in June, well before the new-case count had peaked. 'And even manual contact tracing is very limited here-we need whatever tool we can get right now to curb our epidemic.' • Traditionally, tracers would ask newly diagnosed patients to list the people they'd spent time with recently, then ask those people to provide contacts of their own. Such legwork has helped to control other infectious-disease outbreaks, such as syphilis in the United States and Ebola in West Africa. However, while these methods can extinguish the first spark or the last embers of an epidemic, they're no good in the wildfire stage, when the caseload expands exponentially.