US coronavirus cases top 12 million. An expert says spread is now 'faster' and 'broader' than ever

The number of US coronavirus cases surpassed 12 million Saturday -- an increase of more than 1 million cases in less than a week.

US coronavirus cases top 12 million. An expert says spread is now 'faster' and 'broader' than ever
The number of US coronavirus cases surpassed 12 million Saturday -- an increase of more than 1 million cases in less than a week.