Pertussis in Pacific Northwest
Pertussis Outbreak Reaches the Pacific Northwest
Washington State Department of Health (WA DOH) has announced increases in pertussis ("whooping cough") infection and the deaths of two infants. For the past several months, California has battled a large outbreak of pertussis with 6431 cases* and 10 deaths. Now in WA there is heightened concern as well. According to the most recent data, pertussis cases in Washington are up by 40% (see Table 1 and Letter from WA State Health Officer). The illness, which is caused by a bacteria (Bordetella pertussis), causes a prolonged cough and is most serious in young infants and the elderly.
* Includes confirmed, probable and suspect cases as reported by CA DOH. CDC reported cases (Table 1) shows 2,277 cases. The discrepancy between the two reporting sources may be due to reporting delays, see footnote, Table 1.
Immunization
Here in the Pacific Northwest, immunization rates for pertussis in 2009 were similar to the national average of 83.9 % of two year olds who had all 4 doses of DTaP (See Table 2).
According to the 2009 CDC National Immunization Survey, coverage in more rural parts of Washington (Eastern/Western) was estimated to be lower than other parts of the state.
Table 2. Estimated Vaccination Coverage* with 4+DTaP Among Children 19-35 Months of Age by Race/Ethnicity, and by State and Local Area—US, National Immunization Survey, Q1/2009-Q4/2009
Table 3. 4th Quarter FY 2010 2 Year-old (19-35 months) Immunizations Coverage, by State and Region, Portland Area Indian Health Service*
The most recent reporting from IHS and Tribal sites shows that in the Portland Area IHS overall, 72.3% of two-year olds are up to date with all four doses of DTaP, ranging from 71.4% in WA to 75.9% in ID. Nationally, 82.5% of two year olds are fully immunized against pertussis. These levels of vaccine coverage are insufficient to keep communities protected from disease outbreaks. Furthermore, within each state, there are communities where immunization coverage is much lower than the average, which creates conditions for an outbreak of pertussis to occur.
The diphtheria-tetanus-acellular pertussis vaccine (DTaP) is routinely given starting at 6 weeks of age to prevent pertussis, but full immunity for children requires at least four vaccines before the age of two and an additional dose given at age 4 or 5 years. Immunity begins to wane in the middle school years so a booster (known as TDaP) should be given to adolescents and adults starting at age 11. Many cases are believed to be linked to adolescents or young adults who have not been fully vaccinated and become ill with mild symptoms that last for several weeks. The long duration of illness and close contact to infants means they are able to pass the infection on to those who are more likely to become severely ill.
What can you do? Make sure the children in your community get all four DTaP immunizations before the age of two, starting at six weeks. And make sure all adolescents receive their TDaP booster starting at age 11.
Questions? Contact the Portland Area IHS Immunizations program for more information at (503) 416-3298 or email
Resources for Clinicians
From State Public Health Departments
- Letter from WA State Health Officer
- Washington Department of Health Press Release
- California Department of Public Health Press Release
- California Pertussis Summary Report, 11-2-2010
2010 Immunization Schedules
Other Resources
- How to Manage a Pertussis Outbreak in Your Practice
- Pertussis: A Disease Affecting All Ages
- Patient handout about “Whooping Cough”
- CDC Morbidity and Mortality Weekly Report, July 9, 2010
Historic Pertussis Disease Information for Idaho, Oregon and Washington:
