According to new year-end data from the Centers for Disease Control and Prevention (CDC), cases of pertussis (also known as whooping cough) in Washington increased by more than 2,200%.
The surge far outpaced the national trend, which saw a 401% year-over-year increase.
According to state data as of Dec. 28, Washington had 2,040 cases of whooping cough in 2024, ranking fifth in the nation. In 2023, the state reported 87. (A PDF of the state’s report can be found here.)
Clark, Spokane, and King counties had the most cases, but Whitman and Chelan counties had the highest prevalence, with rates of illness reaching 169 and 180 people per 100,000, respectively. The disease was detected in at least 33 of Washington’s 39 counties.
State health officials had previously warned the public, telling Washingtonians in a press release on November 7 that they were “closely monitoring the situation,” while federal health officials explained the increase as a “return to more typical trends” following the COVID-19 pandemic.
No official cause revealed, but vaccines are urged
The state’s release did not specify a direct cause, but officials urged the public to renew vaccinations.
“The surge in pertussis cases is a stark reminder of how critical vaccinations are in protecting our most vulnerable, especially infants for whom it can be life-threatening,” said Dr. Tao Sheng Kwan-Gett, chief science officer at the Washington State Department of Health.
“To protect babies from whooping cough, people of all ages should get up to date on pertussis vaccination, and anyone with symptoms should see a health care provider to see if testing and antibiotic treatment are needed.”
Nationally, the United States recorded 35,435 cases in 2024, the highest number since 2012.
While it represents a significant increase over the country’s 2023 total of 7,063 cases, officials compared last year’s spread to pre-pandemic levels, which were typically more than 10,000 cases per year.
A piece on the CDC website cited the pandemic specifically as the reason why numbers have dropped in recent years ahead of 2024.
“It’s likely mitigation measures used during the pandemic (e.g., masking, remote learning) lowered transmission of pertussis,” according to the agency.
