Officials look to smartphone data to stem the spread of virus.

Britain, Germany and Italy are evaluating powerful and invasive tools for what epidemiologists call contact-tracing, the mapping of personal interactions that could spread the virus. These apps would use realtime phone data to pinpoint virus carriers and people they might have infected.

That worries privacy advocates, who fear such surveillance could be abused without careful oversight, with potentially dire consequences for civil liberties.

“These are testing times, but they do not call for untested new technologies,” a group of mostly British activists said in an open letter Monday to the country’s National Health Service.

The new tools would mark a substantial departure from existing European disease-surveillance efforts, which have focused on tracking people’s movements with aggregated phone location data designed not to identify individuals. Italian police also began mobilizing drones on Monday to enforce restrictions on citizens’ movements.

But there is a powerful argument in favor of more powerful digital tools, even if they shred privacy: They have been used by several of the Asian governments most successful at containing the pandemic locally, including in China, Taiwan, Hong Kong, South Korea and Singapore.

Last week, Israel took the most invasive step yet by charging its Shin Bet domestic security agency with using smartphone location-tracking to track the movements of virus carriers for the prior two weeks, using historical data to identify possible transmission.

So far, there’s no indication the U.S. government plans to track identifiable individuals for disease surveillance. A spokesperson for the White House Office of Science and Technology Policy said it was not currently working on such an app.

The Centers for Disease Control and Prevention did not immediately respond to questions from The Associated

Press.

The White House has reached out to big tech companies for help in the worst pandemic in a century, but Google and Facebook both told the AP they are not sharing people’s location data with governments.

A Google spokesperson said the company was exploring ways to use aggregated location information against COVID-19, but added that the location data Google normally gathers from phone users isn’t accurate enough for contact tracing.

An AT&T spokesperson said the company was not sharing real-time location tracking with U.S. government virus-trackers. Sprint declined to comment and Verizon did not immediately respond to a query.

While legal safeguards exist in most democracies to protect digital privacy, the danger of the coronavirus could quickly compel policymakers to ignore them. On Friday, the European Union’s Data Protection Authority cautiously endorsed putting privacy on pause during the public health emergency.

ALESSANDRO GRASSANI/THE NEW YORK TIMES A woman stands on a balcony on March 15 in Milan. Italy is under a national quarantine because of the coronavirus, which has killed more than 6,000 people in the country.