There are more than four times as many cases of whooping cough this year compared to last year in the U.S., with the highly contagious disease spreading at its fastest pace in years just as back-to-school season kicks off.
Data published by the Centers for Disease Control and Prevention on Thursday shows there were 291 cases of whooping cough, or pertussis, last week, adding up to 14,569 cases this year compared to last year's 3,475.
The cases were widespread across the country: Many states had under 10 cases, while New York saw the most with 44 and Pennsylvania 38. Ohio saw 39 and Oklahoma 40, while Alaska had 14 and Florida saw 22.
There haven't been this many whooping cough cases in a single year since 2019, when the U.S. saw 18,617 total cases, CDC data shows. Since then, case numbers had been on the decline, staying under around 6,000 until this year's return to pre-pandemic levels. Officials say that's likely due to the cooling off of preventative actions that were used during the pandemic, like good hygiene and distancing, that lowered transmission of the disease.
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Whooping cough is a respiratory illness caused by pertussis bacteria that can cause airways to swell. When a person with the bacteria sneezes or coughs, others can breathe in the small particles they release into the area, easily spreading the disease that can remain contagious for weeks.
Once infected, symptoms will often start like a common cold within five to 10 days, but they vary by age. A week or two later, coughing fits marked by the "whoop" noise people make when gasping for air afterward begin, which can cause difficulty sleeping and breathing, vomiting, fatigue and even fractured ribs, the CDC says.
Newborns and unvaccinated children are at the highest risk of serious illness caused by the disease, but health officials have warned of more cases in adolescents and adults amid rising vaccine and booster hesitancy. And because protections from the vaccine decrease over time, even those who have been vaccinated against the disease before aren't as safe as they once were.
The CDC recommends whooping cough vaccinations for all Americans — and boosters at least every 10 years. Pregnant women are also encouraged to get a booster during their third trimester to pass some protection to their fetuses, with the federal agency saying this prevents more than 3 in 4 babies younger than 2 months old from getting the disease.