Big Tech failed with contact tracing. Can it do better with vaccine passport apps?

As some US cities start requiring proof of vaccination to enter restaurants, events and workplaces, smartphone makers such as Apple, Samsung and Google are rolling out ways to make it easy for users to show their Covid-19 vaccine status with just a tap.

It could be Big Tech's shot at making a dent with pandemic solution tools following its failed attempt last year at contact tracing apps, which used Bluetooth technology to alert people if they've been in close proximity with someone who tested positive for the virus. Those products were plagued by issues around measuring proximity while keeping data anonymous, notifications that failed to trigger and slow adoption rates among states. On paper, this latest effort should be much simpler, but the companies face a crowded app market and the potential for privacy concerns among some Americans.