MISSOULA, Mont. (AP) — Ravalli County health officials trying to stop a whooping cough outbreak are banning all unimmunized students from schools in Corvallis and Victor until May 13.

Public Health Director Judy Griffin tells KECI-TV that any student who hasn't been vaccinated for pertussis — whether it's for religious or health reasons — will miss 21 days of school.

She says the decision was made to protect the general public, including babies that have no way of being fully immunized against the bacterial infection that can cause uncontrolled coughing.

Griffin says 22 cases of whooping cough have been confirmed in the county.

Corvallis Superintendent Monte Silk says teachers will prepare work for the students who are out of school and they will be allowed to make up any missed tests when they return to classes on May 13.