Health Advisory: Pertussis Increase in Washington State

Current Situation in Washington

There have been a total of 170 confirmed and probable cases reported statewide during 2024 through 5/4/2024 (CDC Week 18), compared to 24 cases reported by CDC Week 18 in 2023, an increase of 6-fold. Multiple jurisdictions have reported increases.

Current information about pertussis in Washington can be found in the DOH Weekly Pertussis Update. This report is updated every Friday.

In Yakima County, there is one confirmed case with three additional epi linked cases.

Persons at high risk for pertussis:

  • Infants <1 year old (who are at greatest risk for severe disease and death)
  • Pregnant persons in the last trimester (who will expose infants)
  • Healthcare workers with direct patient contact (who may expose infants, pregnant persons, or others who have contact with infants or pregnant persons)
  • Anyone who may expose infants < 1 year old or pregnant persons (e.g., childbirth educators, child care workers, members of a household with infants).

Actions Requested

  • Be aware of an increase in pertussis reported in some areas of Washington State and that patients with a history of receiving pertussis vaccine can still get pertussis. Consider the diagnosis of pertussis in the following situations:
    • Respiratory symptoms in infants <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.
  • Consider testing. 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.
    • Please note that 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.
  • Report clinically-suspected pertussis cases within 24 hours to the Yakima Health District, who will assist you in determining recommendations for prophylaxis and exclusion.
    • Call (509) 249-6541.
  • Assure children and adults are up-to-date on pertussis-containing vaccine as recommended by national guidelines. Current vaccine schedules can be found on the CDC Immunization Schedules webpage.
    • Prioritize vaccination of household members and other close contacts of infants.
    • Tdap is recommended during each pregnancy after 20 weeks gestation (ideally during weeks 27 through 36).

If you strongly suspect pertussis:

  • Treat: CDC provides detailed treatment guidance.
  • Exclude: tell the patient to stay home from work, school, or childcare. Advise them that they are considered contagious until they have completed 5 full days of appropriate antibiotics. 
  • Report the illness to the Yakima Health District within 24 hours.
  • Consider preventive antibiotics for the entire household if a member meets any “High Risk” criteria (above).

Diagnosing pertussis can be difficult, particularly during the early (catarrhal) stage of illness, which features non-specific symptoms and may not initially include a cough. For a patient with respiratory symptoms, known or suspected exposure to pertussis should prompt inclusion of pertussis in the differential diagnosis. The incubation period for pertussis ranges from 5 to 21 days. A key feature that distinguishes pertussis from other common respiratory illnesses is the duration of the cough (usually longer than two weeks, and can last 10 weeks or longer).

Resources for Providers

To report suspected cases, or for any other questions about pertussis, please contact:

Yakima Health District

(509) 249-6541