Washington likely to see ‘epidemic year’ of whooping cough, Snohomish County doctor says

Washington State is seeing a dramatic rise in the number of cases of pertussis, also known as whooping cough, the WA State Department of Health said, including in Snohomish County.

There are more than 200 reported cases across Washington as of mid-May, according to the Washington State Department of Health, compared to 24 cases that were reported for the same period in 2023.

In Snohomish County, health officials said there are currently 10 confirmed or probable cases of the disease across the county, which is more than three times the number of cases the county saw in each of the last three years.

“We are likely entering an epidemic year for pertussis,” Dr. James Lewis, Health Officer for the Snohomish County Health Department, wrote in a statement. “This would occasionally occur pre-pandemic, and this year’s resurgence of pertussis could be larger than a typical epidemic year prior to the COVID-19 pandemic. Many folks have fallen behind on immunizations and that, combined with the lack of pertussis circulating in recent years, has likely decreased overall immunity within the broader community.”

As of late May, six of the 10 reported cases involve children younger than six years old, officials said.

However, the recent cases also include people up to 65 years old and older, they added.

A spokesperson for the Edmonds School District told KIRO 7 News that the district is currently working with the county health department to address recent reported cases at Mountlake Terrace High School.

KIRO 7 News asked the district for more details, including if the cases involved students or staff and the number of cases that have been reported.

The district did not share those details and shared the following statement.

“The Edmonds School District is working closely with the Snohomish County Health Department to address recent pertussis cases at Mountlake Terrace High School. We have notified staff, students, and families at the school about the situation and are following recommended guidance to prevent further spread. We encourage everyone in our community to check their vaccination status and get immunized if needed. For more information on pertussis and prevention, please contact the Snohomish County Health Department.”


Pertussis is a potentially serious illness caused by bacterial infection, officials said.

The disease’s impact is typically mild for adults and older children, they added, however, it could be deadly for infants.

“Infants can end up hospitalized and the disease can be fatal for them,” officials wrote in a press release.

KIRO 7 News spoke with Lelach Rave, a pediatrician with 25 years of experience, to learn more about the disease.

“It’s actually really contagious. About eight in 10 folks who are not immune, if they’re exposed to someone with whooping cough, will catch the disease,” said Rave.

Rave said pertussis is not a common disease since most of the population is protected.

She said most infants receive a series of vaccinations to protect themselves beginning at two months old.

Many often later receive a booster shot at 11 years old, she added.

“The people who really get sick are babies and when whooping cough is in a community and babies are impacted, it’s pretty typical for them to require hospitalization and very intense medical support,” Rave told KIRO 7 News.

County health officials said there are no reported deaths related to pertussis in Snohomish County this year.

Rave said the COVID-19 pandemic may have played a factor in the recent trend.

“We saw a big decline in vaccination rates because people weren’t going to the doctor. They weren’t going anywhere and so, some of those folks still haven’t caught up on their vaccines, and so that could perhaps be a reason you might have a population of kids who are not protected the way they might have been,” she said.

The local pediatrician told KIRO 7 News that vaccinations can limit, and potentially stop, the disease from spreading.

“Hopefully what this could do is encourage people to get vaccinated if they haven’t vaccinated their kids so that we can kind of stop it in its tracks. That would be the goal,” she said. “Women who get the vaccine late in their pregnancy are giving their babies protection, which covers them until that two-month mark where they get their own vaccine for the first time.”

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