Contact tracing has long been used to combat the spread of sexually transmitted diseases like syphilis in the 1930s, and HIV in the 1980s. But the practice has raised privacy concerns.
A year ago, public health workers contacted people who had been exposed to measles, a nearly-eradicated disease that has been gaining an occasional foothold among those who aren’t vaccinated against the virus.
Now with the coronavirus, contact tracing is going digital. Apple and Google are creating phone software that will alert users who have been near someone who has tested positive for the virus.
There are potential pitfalls for privacy and accuracy. In South Korea, government surveillance data revealed enough information about a woman with Covid-19 that she was identified and harassed online. A woman in Israel was quarantined after merely waving to an infected person from outside his apartment.
“Exposure notification” apps using phone data are being tested in the United States as concerns grow about what personal information will be gathered and how it will be used and stored. States are hiring thousands of workers to do person-to-person outreach to anyone exposed to the virus.