Why Many Countries Failed at COVID Contact-Tracing — But Some Got It Right

The reasons for the failures are complex and systemic. Antiquated technology and underfunded health-care systems have proved ill-equipped to respond. Wealthy nations have struggled to hire enough contact-tracers, marshal them efficiently, or make sure that people do self-isolate when infected or that they quarantine when a close contact has the disease. And overstretched contact-tracers have been met with distrust by people wary both of health authorities and of the technologies being deployed to fight the pandemic.

A handful of places stand out as exemplars of successful contact-tracing — including South Korea, Vietnam, Japan, and Taiwan. Many of these have cracked down on COVID-19 early, isolated infected people and their contacts, and used personal data such as mobile-phone signals to track obedience. Not all of those techniques are transferable to countries now struggling to contain massive outbreaks. But they still provide some lessons.