People in parts of US where COVID-19 infections are surging are required to wear masks indoors even if they are fully vaccinated against the virus.
Citing new information about the ability of the Delta variant to spread among vaccinated people.
The US Centers for Disease Control and Prevention, also recommends indoor masks for all teachers, staff, students and visitors to schools, regardless of their vaccination status.
The US is averaging more than 57 thousand coronavirus cases a day with 24 thousand hospitalizations.
Public health officials have for weeks warned that COVID-19 infections are increasing.