MISSOULA, Mont. -

Six new cases of whooping cough have been confirmed in Ravalli County, bringing the total to 28. The county's board of health has temporarily banned all students from school who haven't been immunized, until the outbreak recedes. That has some parents angry.

"There is no way that keeping my child out of school is going to help this problem," one NBC Montana viewer told us via email. "She is still going to see people from school outside of school, along with exposure to the general public."

Others disagree. "It puts every other child at risk, and I think that's a very unfair thing to do," Hamilton resident Priscilla Peterson said. "It's your choice to not vaccinate, but it's the County Health Department and the schools' choice then to ask you to keep your child at home."

Health officials say one of the latest cases is the third at the Ravalli County Head Start in Hamilton.

Ravalli County Public Health Director Judy Griffin has worked here at the department for more than two decades. She says this is the worst whooping cough outbreak she's ever seen.

"I still really urge their parents to get them vaccinated, to really think about it," she said. "And as I've said many times before, this is the only way we're going to stop outbreaks of this nature."

Peterson, 72 years old, is getting her vaccination Monday. "I do have a lung situation so for me, it could possibly kill me," she said.

If you are planning to get a whooping cough vaccination in Ravalli County, you may want to do it sooner rather than later. The price is scheduled to go from $50 to $57 on May 7.