MINNEAPOLIS (WCCO) — Duluth Public Schools will require masks indoors starting Monday, the district announced.

The mandate applies to all students age 2 and older, all district employees and the public, except in cases of medical exemption. It also applies to both vaccinated and unvaccinated individuals alike.

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The district said the mandate “runs until further notice” and that a final decision for the school year will be announced by Aug. 24.

Minneapolis Public Schools also announced a mask requirement Thursday. St. Paul Public Schools intends to settle its mask requirements in the next two weeks.

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COVID-19 cases are expected to surge over the next two weeks, thanks to the easily-transmissible Delta variant. At least two-thirds of Minnesota counties are now considered at high or substantial risk of spreading the virus, including the bulk of the Twin Cities metro area.

COVID-19 cases among kids are rising, just weeks away from the start of school. The CDC reports that, for the week ending July 29, there were 72,000 cases of COVID-19 in kids under 18. The week before, there were 40,000 cases. Top doctors from the Mayo Clinic say data from summer camps has given them concrete evidence for why kids need to mask up in schools.

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Dr. Nipunie Rajapakse said “in summer camp settings that used masks or didn’t use masks, the ones they were not using masks in were much more likely to have outbreaks or spread of infection.”