Skip to main content



Also known as Whooping Cough

Pertussis, also known as "whooping cough," is a toxin-mediated respiratory illness 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

Resources for health care professionals

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.