BOSTON (AP) — Massachusetts has purchased 200,000 at-home testing kits that will be distributed to school districts throughout the state so teachers and staff can test for COVID before they return to work after the holiday break, school officials said Wednesday. Tests are not required to return to school.

Every district will receive enough tests to ensure that two can be distributed to each staff member, one of which should be taken no more than 24 hours before they return to work, with the second kept to be used at the staffer’s discretion, the state Department of Elementary and Secondary Education said in a statement.

There were about 8,500 student cases and 1,500 employee cases confirmed in the state’s public schools for the week that ended December 23, the latest data available. The state’s public schools have about 920,000 students and 140,000 employees.

Last week, the state distributed more than six million KN95 masks to schools for employees. “Doing everything we can to keep students learning in classrooms is critical. Providing these tests to teachers and staff is one more thing we can do to ensure that is possible,” Education Commissioner Jeffrey Riley said in a statement.

The University of Massachusetts is making COVID vaccine booster shots mandatory for 75,000 students and 18,000 faculty and staff across all five of the system’s campuses. Students and employees were required to receive vaccines for the fall semester, which the university in a statement said resulted in nearly 100% compliance and COVID positivity rates well below national and state averages across the system.

Over 300 employees at the president’s office are also required to get a booster shot as soon as reasonably possible after they become eligible, the statement said. Employees who have been granted a religious or medical exemption from the vaccination requirement are exempt from the booster requirement. The system has campuses in Amherst, Boston, Dartmouth, and Lowell, and a medical school in Worcester.