Pertussis in Cascade County

Great Falls, MT – Cascade County has confirmed its first case of pertussis in 2023. Although only one case has been confirmed, it involved a large number of exposures. There are multiple other suspected pertussis infections that have not been confirmed through laboratory testing. Statewide, 17 pertussis cases have been confirmed in 2023.

Pertussis, also known as whooping cough, is a highly contagious respiratory infection that spreads through droplets produced by coughing or sneezing. It is most dangerous in infants, pregnant women, and people who are immunocompromised. Symptoms typically appear 7-10 days after infection and include malaise, a mild fever, runny nose, and cough that gradually develops into a hacking cough, and can lead to pneumonia or seizures.

Persons experiencing these symptoms should seek testing and care at a clinic or medical facility and should wear a mask around others. Other persons in close contact with symptomatic individuals, including family members, medical personnel, and emergency responders, should also wear masks and eye protection. Persons testing positive or experiencing symptoms following exposure should stay home and avoid contact with others until test results return negative or until completion of an antibiotic prescription, and all household members of a person with pertussis should be treated with post-exposure prophylaxis (PEP) antibiotics, regardless of immunization status. Unimmunized children under age 7 who have been exposed should be removed from school and daycare, even if asymptomatic, until completion of PEP antibiotics or 21 days after exposure.

People immunized for pertussis typically have less severe symptoms but can still spread the infection. The recommended series of immunizations is:

- DTaP (Diphtheria, Pertussis, & Tetanus) at 2 months, 4 months, 6 months, 15-18 months, and 4-6 years

- If a DTAP series was completed, then a dose of Tdap should be given at age 11-12; if the DTaP series was not completed according to ACIP guidelines, then a Tdap may be given as soon as age 7 and ACIP catch-up schedule should be followed

- Any adult age 18+ who has not received a primary vaccination series for tetanus, diphtheria, or pertussis should receive a 3-dose Td or Tdap series

- All adults should receive a Td or Tdap booster every 10 years and, if under 65 and never received a pertussis-containing vaccine as an adult, at least one dose should be Tdap

- Women should receive an additional dose of Tdap during each pregnancy, preferably during gestational weeks 27-36

Anyone not already immunized for pertussis is advised to seek immunization from their medical provider. Immunization is available at CCHD by appointment (406-454-6950). Pertussis and other childhood immunizations will also be available at the annual Back To School Clinic on August 9, 2023. More information about immunization is available at https://www.cascadecountymt.gov/396/Immunizations.