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Public Health - Seattle & King County

Pertussis (Whooping Cough)

Pertussis, also known as "whooping cough," is a toxin-mediated disease caused by the bacteria Bordetella pertussis. It is spread primarily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes The disease is of particular concern in infants because they have higher rates of pneumonia, hospitalization, and death compared with older children and adults. Pertussis vaccination reduces the frequency and severity of disease. However, the protective effects of natural pertussis infection and pertussis vaccine wane with time. Unrecognized infections in older children and adults are the most common source of pertussis transmission to infants in the community. The primary strategy to prevent severe pertussis among infants is maternal vaccination during the 3rd trimester of each pregnancy.

Resources for the general public

Young parents and infant child

Pertussis facts
Also available in Chinese, Korean, Russian, Somali, Spanish and Vietnamese

Pertussis — what you need to know, CDC

Pertussis vaccination information, CDC

Whooping cough flyer for pregnant women
Patient education flyer with information on how pregnant women can protect themselves and their babies from pertussis.

Resources for health care providers

Doctor with young patient and mother

Issue Brief — Pertussis in Infants
Summarizes local epidemiology and prevention recommendations

Pertussis clinical information (CDC):


  • Reporting requirements. Health care providers, health care facilities, and laboratories are required to report cases of pertussis in King County residents within 24 hours by calling 206-296-4774.

Pertussis in King County

Purpose of surveillance:

  • To prevent transmission of pertussis to infants and other persons
  • To identify outbreaks and implement disease control measures including vaccination and early recognition, testing, and treatment of cases

Pertussis Case Data

Local epidemiology:

In 2014, 140 confirmed, probable, and suspect cases of pertussis were reported, compared to a five-year average of 253 cases and to the 2012 outbreak year, when 895 cases were reported. Children under the age of one accounted for just six cases. Five cases were hospitalized, including three infants; no deaths were reported. Case reports increased notably during November, 2014, predominantly among high school-aged children.

Typically between 400 and 1,000 pertussis cases are reported each year in Washington state, though 4,920 cases were reported in 2012. Pertussis epidemics follow a cyclic pattern, with peaks every two to five years. Lower numbers of pertussis cases are expected in the years immediately following large outbreaks such as the one Washington state experienced in 2011-12.