https://www.theverge.com/2018/4/2/17188922/grindr-hiv-status-privacy-data :
Grindr has been sharing people’s HIV statuses and test dates with two companies that help optimize the app, called Apptimize and Localytics, BuzzFeed reports. Because the HIV info is shared along with GPS data, phone IDs, and email addresses, it makes it possible to link specific Grindr users with their health condition.