Reportedly happening in Israel, though they don't call out the method of cellular tracking they use: https://www.haaretz.com/israel-news/coronavirus-cases-in-is

Reportedly happening in Israel, though they don't call out the method of cellular tracking they use: https://www.haaretz.com/israel-news/coronavirus-cases-in-israel-spike-to-164-nearly-2-500-medical-officials-quarantined-1.8671075 https://www.haaretz.com/israel-news/coronavirus-cases-in-isr... ... The government approved the tracking of cellphones by the Shin Bet security service in order to inform people who were unwittingly close to someone diagnosed with the virus during the two weeks prior to the diagnosis. ...