An introduction to the technology of contact tracing and its usefulness for public health, considering questions of efficacy, equity, and privacy.
Contact tracing is key to containing and controlling the spread of a virus in a pandemic. South Korea, China, and Singapore were among the few countries that quickly employed contact tracing after the emergence of COVID-19; the United States did not. In People Count, cybersecurity expert Susan Landau offers an accessible examination of the technology and efficacy of contact tracing in a pandemic. Can we repurpose the tracking technology that we carry with us—devices with GPS, Wi-Fi, Bluetooth, and social media connectivity—to serve public health in a pandemic?
Landau explains how contact tracing—the careful mapping of the virus's route from person to person—starts as a people-to-people effort, and she looks at what role technology might play. Can it really help? GPS locates people outdoors—but COVID-19 largely spreads indoors. Bluetooth does track people inside—even through walls, which is not how COVID-19 spreads. So when can such technology be efficacious? Landau explains the effectiveness (or ineffectiveness) of a range of technological interventions, finding that cellphone location data is not precise enough to trace close contacts. She describes tracing methods that protect privacy, including encryption and aggregation. She considers issues of equity—the disparate effect on different communities—and the long-term social impact of contract-tracing technologies. COVID-19 will not be our last pandemic; we need to get this essential method of infection control right.