NBC News - The Centers for Disease Control and Prevention recommended Tuesday that all students in kindergarten through 12th grade should wear masks when they return to schools this fall.
The newly issued CDC guideline includes youngsters who have already been vaccinated.
Last week, the American Academy of Pediatrics also recommended that children 2 and older should wear masks when they go back to school.
Children 12 and older are now eligible to be vaccinated against Covid-19.
More than 163 million Americans have been fully vaccinated, according to CDC data on Tuesday, though public health officials are concerned that the sizable un-vaccinated population is contributing to rising cases of the virus' Delta variant.
The Biden administration is set to recommend indoor masking for anyone in areas of high transmission.