Apple and Google are leveraging smartphone technology to contain the COVID-19 pandemic in a momentous joint effort. New software the companies plan to add to phones would enable the use of Bluetooth wireless technology to track down people who may have been infected by coronavirus carriers. The idea is to help governments roll out apps for so-called “contact tracing” that will run on iPhones and Android phones alike. Developers have already created such apps in countries including Singapore, China and the Czech Republic _ but some use location data and are invasive. Apple and Google say user privacy and security are baked into their design.