Kansas City, Kan. ? The Kansas City, Kan., School District is cracking down and strictly enforcing a state law that requires children to be immunized in order to attend classes.

Officials estimate that 2,000 of 19,000 students weren’t compliant on mandatory vaccines.

The Kansas City Star reports that the district sent letters home to parents before school started explaining the state law that forbids children from attending school unless they vaccinated.

In the past the district had allowed students a several-week grace period to get their required shots.

Administrators acknowledged that immunization policies were not uniformly enforced in the past. But this year the district held to its decision and students were sent home as deficiencies were discovered.