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MISSOULA - Authorities say six confirmed cases of whooping cough are under investigation, and they've identified 300 people who may have been exposed to the disease.

The city-county health department says the six cases are in children aging from preschool to teenager, and one child has been hospitalized. More cases are awaiting test results.

Sentinel High School says three of their students have tested positive.

The confirmed cases are a mix of vaccinated and unvaccinated kids, a release says.

The health department says they will directly contact families if their children could have been exposed to the disease.

You can call the health department's info line at 406-258-INFO if you have questions.

Whooping cough, formally known as pertussis, begins with cold-like symptoms and progresses into a persistent, severe cough. Visit a walk-in clinic for testing if you're experiencing the symptoms.

It's advised that anyone who hasn't received the full pertussis series, including pregnant women, are urged to update their vaccinations.

Read the full Missoula City County Health Department release:

Health Department Investigating Several Pertussis Cases in Missoula Area

The Missoula City-County Health Department is currently investigating six case of pertussis (whooping cough) in the Missoula area and has identified more than 300 close contacts who may have been exposed to the disease. Ages for the confirmed cases range from preschool through teenager, with one case requiring hospitalization. Additional suspected cases are pending laboratory results. There is a mix of unvaccinated and vaccinated children among the cases. 

The health department is working directly with the affected families and the schools the ill children attended to identify close contacts. Pertussis is spread by respiratory droplets, so while it is highly contagious, not everyone who goes to the same school as a child with pertussis is considered a close enough contact to have been exposed.

When a close contact is identified, the health department will notify the child and the child’s parents. Health officials request that parents do NOT call the health department or their child’s school to determine if their child has been exposed. For other questions about pertussis, please call the health department pertussis information line at 406-258-INFO.


With an outbreak underway in the Missoula area, there may be more active cases of pertussis in the community that health officials don’t know about yet. If treated in its early stages, pertussis symptoms can be reduced, and close contacts who have been exposed can be protected from developing the disease. Anyone experiencing the pertussis symptoms described below should contact their healthcare provider or go to a walk-in clinic for testing. Immunization provides good but not full protection against pertussis, so people can get the disease even when vaccinated. 

Pertussis, also known as “whooping cough,” typically begins with cold-like symptoms, including a runny nose, mild occasional cough, sneezing and low-grade fever. Later symptoms include a persistent cough with fits of coughing severe enough that exhaustion, vomiting or a whooping sound may occur as the patient tries to catch their breath. Symptoms can be more severe in unvaccinated individuals, babies less than a year old and those with compromised immune systems. 

Residents are encouraged to check their vaccination status by calling their doctor or the health department’s Immunization Clinic at 406-258-3363. People who have not received the full pertussis series, including a booster, and women who are pregnant, even if they were fully immunized before pregnancy, are urged to update their vaccinations.  

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