A train operator has been placed on leave after at least 25 people received medical attention when two trains crashed in Boston.
Author: Jeanine Santucci and Christine Fernando, USA TODAY
Start of Olympics prompts COVID-19 concerns; delta one of most infectious respiratory viruses ever, CDC director says: Latest updates
CDC director Rochelle Walensky told reporters ‘the delta variant is more aggressive and much more transmissible than previously circulating strains.’