MISSOULA, Mont. -

Missoula health officials figure they've got a whooping cough outbreak under control with a total of eight cases.

Some of the sick had already been immunized, but experts say when they get sick, they are likely to have milder symptoms.

Missoula City-County Health Department Director Kate Siegrist said it is important for folks to get immunized.

"What we think of vaccines they boost your immune system. They work to actually prevent pertussis about 80 to 85 percent of the time, but even if you do develop pertussis and you've been vaccinated it is likely that the course of the disease will be more mild," Siegrist said.

Siegrist said getting the community immunized will help keep the outbreak contained.

She said so far since April 461 citizens have gotten their TDAP (Tetanus, Diphtheria and Acellular Pertussis) vaccine, that is up from 136 during this time last year.

Siegrist said they are thankful the community is being proactive about immunizations.

Because it is considered an outbreak Siegrist said health officials are keeping an eye out on symptoms.

"We're paying more attention to symptoms, because we want to catch those cases of pertussis early to prevent the spread in our community so if you've had a persistent cough for over a week you need to see your health care provider," Siegrist said.

To access the Missoula City-County Health Department's website and for more information on vaccines click here.