Washington State Pertussis Epidemic Highlights Importance of Vaccination

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In early April, the Washington State Department of Health declared a pertussis (whooping cough) epidemic. The state has seen over 1,200 cases so far this year, and officials suspect there will be at least another few thousand cases before year’s end; levels that haven’t been seen in over 60 years. In response to the declared epidemic, the state has been working to make vaccines more accessible to uninsured patients. Additional response measures have included urging employers to encourage employee vaccination and instructing hospitals to vaccinate new parents.


Washington State Secretary of Health, Mary Selecky, said [1]:

We’re very concerned about the risk to infants, especially because of how quickly whooping cough is spreading. Whooping cough can be life threatening for infants, and they’re too young to get enough doses of vaccine to be protected. That’s why we want everyone else to make sure they’re vaccinated against whooping cough.

Pertussis is a very contagious respiratory infection caused by the Bordatella pertussis bacterium. Infected individuals experience severe, long-lasting coughing fits that leave them gasping for air. The prolonged coughing empties the lungs of air, which causes a gasping inhale that results in the characteristic “whooping” sound associated with pertussis. The disease is spread through the air; casual contact with an infected person is often sufficient to cause infection. Infants are particularly susceptible, and are also more likely than adults to become dangerously ill if infected; more than 50% of infants with pertussis require hospitalization, and of those, one in 100 will die.

Symptoms of early pertussis are similar to those of a cold, and last 1-2 weeks. The next stage of pertussis is more serious, and can last up to 10 weeks. It’s during this second stage that the paroxysmal coughing occurs. The coughing is often so protracted and violent that it results in vomiting and exhaustion. It takes an additional 2-3 weeks to recover from the illness, resulting in a total illness duration of up to three months.

There is a vaccine available for pertussis, which is generally given in combination with the vaccines for tetanus and diphtheria. The combined vaccine is called the TDaP (for adults) or the DTaP (for children). Children require a series of 5 DTaP shots starting at age 2 months to develop initial immunity; an incomplete series of shots does not provide adequate protection. Adults need a TDaP booster once every 10 years. Making sure adults are up to date on vaccination is a critical public health measure, as it helps to protect infants with whom they come into contact who are too young for immunization or have not yet completed their immunizations.


  1. Whooping cough case count passes 1,000 cases in WA — epidemic continues. Washington State Department of Health. 2012 Apr 24.
About the Author

Kirstin Hendrickson, Ph.D., is a science journalist and faculty in the Department of Chemistry and Biochemistry at Arizona State University. She has a PhD in Chemistry, and studied mechanisms of damage to DNA during her graduate career. Kirstin also holds degrees in Zoology and Psychology. Currently, both in her teaching and in her writing, she’s interested in methods of communicating about science, and in the reciprocal relationship between science and society. She has written a textbook called Chemistry In The World, which focuses on the ways in which chemistry affects everyday life, and the ways in which humans affect each other and the environment through chemistry.