Fully vaccinated people who get a breakthrough infection can transmit the virus, US Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said in an interview with CNN's Wolf Blitzer. That's why the CDC changed its guidance last week and is now recommending even vaccinated people wear masks indoors again, Walensky said. CDC provided data last week that showed how fully vaccinated people who get a breakthrough infection can carry essentially that same amount of virus as an unv