A Mississippi school district that started the new school year a week ago with a face mask optional policy has now closed three of its schools due to COVID-19 coronavirus outbreaks and has reinstated a mandatory mask policy for students and staff.

The Lamar County School District had started classes a little more than a week ago without requiring face masks. Late last week, the district announced Friday that two high schools – Oak Grove and Purvis high schools — would close and students switch to virtual learning after COVID-19 outbreaks at the schools.

District leaders also reinstated mandatory face mask usage Friday for all other schools in the district.

On Tuesday, a third Lamar County school – Oak Grove Middle School – was closed to in-person learning and switched to virtual learning for approximately two weeks, district officials announced.

The district reported late last week that approximately 140 students and staff tested positive for the virus and 649 were quarantined after exposure to someone with the virus.

The Centers for Disease Control and Prevention, the Mississippi State Department of Health and the American Academy of Pediatrics have issued guidelines that include, among other mitigation measures, that school districts require face masks in schools. Mississippi has no mandate and Gov. Tate Reeves has said through a spokesman that he doesn’t plan on issuing such a requirement.

That leaves the decisions up to local school districts.