A top U.S. health agency on Tuesday altered its COVID-19-related guidance once again, telling people to wear masks in some areas even if they are fully vaccinated against the virus that causes the disease.
New research into outbreaks from several states and other countries “indicate that on rare occasions some vaccinated people infected with the Delta variant after vaccination may be contagious and spread the virus to others.” Dr. Rochelle Walensky, the director of the Centers for Disease Control and Prevention (CDC), told reporters on a call.
