Healthcare Advisory: Increased Pertussis activity in Kitsap County
- 6 hours ago
- 4 min read
Pertussis activity is increasing in Kitsap County. Kitsap Public Health District (KPHD) recently identified a cluster of cases in two North Kitsap schools and has worked with the school district to notify families and staff of potential exposures. KPHD is working with partners to reduce the impact of this situation.
ACTIONS REQUESTED
Be aware of increased pertussis activity in Kitsap County.
Consider testing and, when appropriate, treating individuals with symptoms consistent with pertussis.
Vaccination remains an important tool to prevent the spread of pertussis and keeping those too young and/or unable to receive vaccination safe and healthy.
Post-exposure Prophylaxis should be considered in certain high-risk populations and their close contacts.
BACKGROUND
Washington state typically reports between 600 – 800 pertussis cases during non-epidemic years, with higher transmission occurring every three to seven years. Transmission was largely disrupted during the COVID-19 pandemic, but surged in 2024, with over 2,200 cases.
Kitsap County similarly experienced a spike in cases during the 2024-25 school year, with 118 laboratory-confirmed and epidemiologically linked cases reported from September 2024 through August 2025. Of these, 51 were associated with two large outbreaks at local high schools. KPHD works with schools and community organizations where cases have been identified to notify people who may have been exposed, and to limit spread in the community.
Although reported pertussis cases declined steeply since the start of the 2025-26 school year, cases continue to be reported throughout the county. We recently identified a cluster of cases in two North Kitsap schools, and have worked with the schools to notify families and staff of potential exposures.
Vaccination for pertussis is recommended in the U.S. and is critical to prevent severe illness in infants, young children and others with underlying conditions placing them at higher risk for severe disease. Around one in 10 Kitsap children entering kindergarten in September 2024 were not up-to-date on their pertussis vaccines. Vaccination of pregnant people is important to protect newborns and infants. Healthcare providers should strongly recommend and offer Tdap vaccination to pregnant people in the third trimester of each pregnancy regardless of prior vaccination.
Weekly state surveillance updates are available online (updated Fridays).
CLINICAL CONSIDERATIONS
People at high risk for severe illness and complications include, but are not limited to:
Infants younger than one year
People with pre-existing health conditions that may be worsened by whooping cough. Some conditions that could be made worse by whooping cough include:
Immunocompromising conditions such as cancer
Moderate to severe asthma, COPD and other chronic respiratory conditions
Consider pertussis infection in the following situations:
Respiratory symptoms in infants younger than 12 months, especially if accompanied by difficulty feeding or apnea
A cough illness, in patients of any age, that is characterized by one or more of the following:
Paroxysms
Gagging, post-tussive emesis, or inspiratory whoop
A duration of 2 weeks or more
Respiratory illness of any duration in patients who have had contact with someone known to have had pertussis or symptoms consistent with pertussis
If you suspect pertussis:
Collect a nasopharyngeal swab for pertussis polymerase chain reaction (PCR) or culture. PCR is the most sensitive and fastest diagnostic test. Culture is the most specific option, but not the most sensitive, and is rarely done. Note that serology should not be used for diagnosing pertussis cases in Washington.
A negative pertussis PCR or culture result cannot rule out pertussis. Treatment and case reporting may still be warranted, even with negative test results, per clinician’s assessment.
CDC provides information about best practices for using PCR to diagnose pertussis.
Report clinically suspected pertussis cases within 24 hours to Kitsap Public Health District. Call Kitsap Public Health 24/7 at (360) 728-2235 during clinical encounters with a suspected pertussis case. We will help determine recommendations for prophylaxis and exclusion.
Advise patients to stay home from work, school, or childcare while waiting for lab result. They are considered contagious until they have completed 5 full days of appropriate antibiotics.
Follow CDC’s detailed treatment guidance. Treatment is most effective if initiated within 1-2 weeks of symptom onset. Presumptive treatment can be a useful tool and should be considered in situations of increased transmission. Early treatment can reduce disease severity and facilitate return to work/school.
Prevention strategies:
Ensure children and adults are up to date on vaccine protecting against pertussis as recommended by national guidelines. Effectiveness of pertussis vaccination wanes over time. Current vaccine schedules can be found on the CDC Immunization Schedules webpage.
Prioritize vaccination of household members, childcare workers and other close contacts of infants.
Tdap is recommended during each pregnancy after 20 weeks gestation (ideally during weeks 27 through 36) given risk for transmission to the newborn.
Ensure routine vaccination of healthcare workers with direct patient contact (especially those who care for infants, pregnant patients and those with other conditions placing them at high risk for severe illness)
Consider prophylactic antibiotics for individuals at high risk for severe illness and their close contacts.
ADDITIONAL RESOURCES
CONTACTING THE HEALTH DISTRICT
Call: 360-728-2235 and leave a message. Includes reporting notifiable conditions 24 hours a day, 7 days a week. Leave the patient’s name, date of birth and disease.
Fax: 360-813-1168
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