Apple, Google building Covid-19 contact tracing tool

Apple and Google revealed on Friday that the two tech rivals are collaborating to launch a contact-tracing app for Covid-19. The system would use a Bluetooth signal that would bounce between users’ mobile phones to trace who they had been in contact with recently.  If that person disclosed they had been diagnosed with Covid-19, everyone they had been in contact with would receive an alert.Contact tracing, or the process of tracing down people that might have come into someone who had been infected, can be time consuming, especially when there are already many cases. The U.S. had more than 501,000 cases as of Friday, according to data compiled by Johns Hopkins University.