Dear Chelan-Douglas Healthcare Partners,
Chelan-Douglas Health District (CDHD) continues to see higher-than-usual Bordetella pertussis (whooping cough) activity in both of our counties. As we alerted you on August 4th, 2026, we have received multiple lab-confirmed cases without epidemiologic linkages, suggesting that the true case count is much more widespread than our numbers suggest. As anticipated, we have seen an increase in cases as schools return to session.
Since June of 2026, CDHD has received 30 cases of pertussis that are lab-confirmed or probable, based on exposure and symptoms. Numerous others have been exposed and warrant post-exposure prophylaxis, or have been exposed and exhibit mild, early-phase symptoms and warrant treatment. We anticipate that you will see an increase in symptomatic and/or exposed individuals seeking care and ask that you provide testing and treatment to help curtail these disease trends.
Schools and school-related activities can be sites of transmission, and often are key components in our surveillance system because schools exclude symptomatic individuals and guide people towards evaluation with healthcare providers. Schools, and our very astute and infection prevention-minded school nurses, identify close contacts and advise preventive actions such as vaccination, symptom monitoring, and seeking healthcare for post-exposure prophylaxis. In household and school settings, post-exposure prophylaxis is very helpful in preventing infections, avoiding complications in high-risk individuals, and in reducing outbreak-related disruptions to school and work.
As such, classrooms may, be included in groups for whom post-exposure prophylaxis is recommended. I have added this recommendation in the bullets, below. Please do not hesitate to contact CDHD for clarification or further discussion about treatment and prevention of pertussis.
Please continue to assist us in our efforts to stop further spread, especially among our most vulnerable populations by taking the following actions:
Remain up to date on the diagnosis, treatment and prevention of pertussis (see links below)
- Consider pertussis for any cough illness, especially with classic symptoms of paroxysms, inspiratory whoop, post-tussive emesis, or apnea
- Consider pertussis for anyone who presents with upper respiratory symptoms and has had contact with a known case of pertussis or someone with a cough illness
- Diagnose with PCR on a nasopharyngeal swab specimen
Upon suspicion of pertussis, based on history, symptoms and physical exam, please:
- Report, upon suspicion of pertussis, to CDHD. Please do not wait for labs to result.
- Treat pertussis with macrolide antibiotics (see resources, below, for selection and dosing)
- Advise isolation (do not go to work, school, camp or other public events) through continuation of antibiotic treatment, or for 21 days after cough onset if patients do not take antibiotics
Provide post-exposure prophylaxis (PEP) for the following individuals:
- Household members and others (including classmates or individuals identified in a school outbreak) who have spent time indoors in close proximity to a confirmed case of pertussis
- Any contacts who are high-risk for severe complications of pertussis, including those who are pregnant, are < 1 year of age, or have chronic medical conditions
- Any individuals who through work, family or social settings may be in contact with the high-risk individuals above
- Please note that if asymptomatic, exposed individuals do not need to be excluded from school or other public activities while taking antibiotics
- If an individual has taken antibiotics for PEP but then develops symptoms, provide an additional course of azithromycin or other appropriate antibiotic regimen
Promote vaccination against pertussis for all patients, as indicated by CDC, AAP, ACOG, and AAFP vaccine schedules
- DTaP at 2, 4, 6 and 12 months of age and 4-5 years of age
- Tdap at 11-12 years of age
- Tdap in each pregnancy
- Tdap once in adulthood
Please also make patients aware that, if they are diagnosed with pertussis, helpful nurses or staff from Chelan-Douglas Health District will call to ensure they are improving, to answer questions about their illness, and to investigate if other people (especially high-risk individuals) are at risk of getting sick. We will continue to provide updates as our investigation continues.
Please reach our CD-EPI Department to report cases or for further information: phone (505) 886-6400, fax (509) 886-6478, or email cd-epi@cdhd.wa.gov.
Pertussis resources for clinicians:
Pertussis Resource, CDC.
Pertussis Resources, DOH.
Pertussis Public Health Guideline, DOH.
Sincerely,
James Wallace, MD, MPH
Health Officer
Chelan-Douglas Health District