DALLAS (CBSDFW.COM) – Many large school districts across the country are tapping the brakes on a return to class as COVID cases surge.

In Chicago the teachers’ union decided all teaching will be done virtually beginning today.

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Here in North Texas, the Dallas Independent School District wants to make sure students have a chance to learn with in-person classes.

Dallas County is back to ‘Level Red’ as the omicron variant of COVID-19 proves to be more contagious. District officials say 256 students and staff members tested positive for COVID this week. The CDC expects the number of positive cases will increase over the next few weeks.

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As a result, DISD has extended its mask mandate until after spring break. It was originally set to expire in January, after Dr. Martin Luther King Day. Despite the surge the district says going virtual again is a last resort.

“We really are trying to do as much to keep our kids in school in person. That’s where they learn best,” said DISD Director of Health Services Jennifer Finley.

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The district is encouraging everyone to get vaccinated. There will be testing available at every campus.

Kennedi Walker