MISSOULA, Mont. -

Ravalli County health officials dealing with an unprecedented outbreak of pertussis banned all students with immunization exemptions in the Corvallis and Victor school districts from attending school until May 13.

Public Health Director Judy Griffin said any student who hasn't been vaccinated for pertussis, whether it's for religious or health reasons, will miss 21 days of school.

"Of course, the decisions you make aren't always popular,? said Griffin. ?We're trying to protect the general public, and we're trying to protect those babies out there that have no way of being totally immunized."

Griffin said twenty-two cases of whooping cough have been confirmed in Ravalli County, many of them students in the Corvallis and Victor school districts.

Corvallis School District Superintendent Monte Silk said on Monday that the plan is for teachers to prepare work for the unimmunized kids to take home, and for them to make up any tests they miss when they return to school on May 13.

Silk said he?s expecting plenty of feedback from parents who aren?t happy with the decision.

"You can't be on school grounds, you can't come to school for 21 days. If you even get a shot tomorrow, you still have another 14 days to wait,? said Silk. (Extra-curricular activities) are the fun part of school. And when you're looking at sports and two state championships on the line, it causes you to think a lot."

Silk said parents can still trust their children won't fall behind.

"They should not worry unduly about the education of their child, because the teachers and the administration will make sure we get them their materials and resources to keep up with school, take their tests when they come back. "