The CDC bought access to location data harvested from tens of millions of phones in the U.S. to perform analysis of compliance with curfews and other patterns, according (https://www.vice.com/en/article/m7vymn/cdc-tracked-phones-location-data-curfews) to CDC documents obtained through a Freedom of Information Act request.
The documents reveal the expansive plan the CDC had to use location data from a highly controversial data broker. SafeGraph, the company the CDC paid $420,000 for access to one year of data to, includes Peter Thiel and the former head of Saudi intelligence among its investors. Google banned the company from the Play Store in June.
The CDC used the data for monitoring curfews, with the documents saying that SafeGraph’s data “has been critical for ongoing response efforts, such as hourly monitoring of activity in curfew zones or detailed counts of visits to participating pharmacies for vaccine monitoring.”