More than 4,700 cases of whooping cough have been reported to the Centers for Disease Control and Prevention this year.
It’s on track to be fewer cases than last year when the CDC estimated more than 28,000 cases. But it’s still a significant number, especially for the states seeing the worst of it.
California reports the most cases of any state with nearly 700 incidents. Washington state reports more than 328 cases this year, and Ohio reports more than 280. Florida reports 262.
Whooping cough, also known as pertussis, is a respiratory illness that is spread easily from person to person through the air. Whooping cough bacteria latch onto the upper respiratory system and release toxins, according to the CDC.
It usually takes five-10 days for symptoms to show up after exposure, though it can take up to three weeks.
Early symptoms typically look like a common cold and can include:
- Runny or stuffed-up nose
- Low-grade fever
- Mild, occasional cough
Later symptoms can include:
- Making a high-pitched “whoop” when inhaling after a coughing fit
- Vomiting during or after fits
- Having difficulty sleeping at night
- Struggling to breathe
- Breaking a rib
“Those who get these coughing fits say it’s the worst cough of their lives,” according to the CDC.
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Infants have the highest reported rate of whooping cough.
“Infants under one year old are at greatest risk for serious disease and death because their immune systems are still developing,” according to the CDC.
Whooping cough cases were lower than usual during and immediately following the COVID-19 pandemic, according to the CDC. But in 2024, it returned to the pre-pandemic pattern of more than 10,000 annual cases.
The pertussis vaccination rate is below target in many states. Among young children who contracted whooping cough last year, only 1 in 5 were fully vaccinated.
“As a result of widespread vaccination use, cases of whooping cough in the U.S. have significantly decreased over the past several decades,” according to Johns Hopkins University’s Bloomberg School of Public Health. “However, we have seen an increase in cases in recent years, in part due to insufficient immunization coverage.”