Whooping cough cases in the United States have reached the highest annual total in a decade, with as many cases recorded in the last 12 weeks as in the entire rest of 2024.
As of mid-September, some 14,500 cases had been recorded nationwide since the beginning of the year. That number rose to more than 32,000 as of December 14, according to data from the Centers for Disease Control and Prevention (CDC).
This is a six-fold increase compared to the same period in 2023, when more than 5,100 cases had been recorded. The 2022 total was even lower, with about 3,000 cases.
Experts attribute the high number of cases to a combination of factors. On the one hand, whooping cough rates fell to levels well below average during the COVID-19 pandemic, so a jump toward pre-pandemic patterns was expected. However, this year’s total is significantly higher than 2019, perhaps due to declining vaccine protection, lower vaccination rates and improved testing.
Also known as pertussis, whooping cough or whooping cough, whooping cough is a bacterial infection that affects the upper respiratory system. Its spread usually follows a seasonal pattern, with a peak in autumn or winter.
The first symptoms may resemble those of a common cold – cough, fever and runny nose – but within a week or two, patients often develop attacks of aggressive coughing during which it is difficult to breathe.
The term whooping cough refers to the high-pitched sound that some infected people make when inhaling after a coughing attack.
“They don’t have time between coughs to breathe,” explained Dean Blumberg, chief of pediatric infectious diseases at the University of California, Davis, Children’s Hospital. “Sometimes, if it’s very serious, children end up being intubated or put on a ventilator so they can receive oxygen.”
Babies are the most vulnerable to whooping cough, at higher risk of becoming infected and suffering serious complications.
“It’s more severe in younger children, so certainly those under one year old, and especially those under 6 months old,” Blumberg said. “I’ve seen one patient die from whooping cough this year, and I’ve seen several who have been in the intensive care unit.”
He added that most of the whooping cough patients he has seen were not vaccinated, and that he has seen a decline in vaccine coverage.
“We have seen more vaccine hesitancy and, unfortunately, more unvaccinated children getting whooping cough,” Blumberg said.
The CDC recommends pertussis vaccines, which protect against this infection, diphtheria, and tetanus, for all Americans two months of age and older. Infants should receive doses of DTPa vaccine at 2, 4, and 6 months, followed by booster doses at 12 to 15 months and again at 4 to 6 years.
One dose of a different formulation of the vaccine, Tdap, is also recommended for preteens ages 11 to 12 and for adults every 10 years.
Vaccination rate falls
Pertussis vaccination rates in the United States remain high, but have decreased over the past five years or so. While more than 94% of children born between 2018 and 2019 had received at least three doses of the DTap vaccine by their second birthday, the rate fell to around 92.5% for those born between 2020 and 2021, according to a report by the CDC published in September.
Among kindergarten-age children, the proportion who had received state-required vaccines – including DTap – fell from 95% in the 2019-20 school year to less than 93% by the 2023-24 school year, the researchers found. CDC in October.
Of children under one year old who were hospitalized with whooping cough last year, only about 29% had received at least three doses of the vaccine, according to the CDC.
Vaccine protection fades over time.
Santina Wheat, a professor at Northwestern University Feinberg School of Medicine, said most of the whooping cough patients she has seen have been vaccinated preteens and adults.
“I think we’re probably seeing some of the effects of waning immunity,” he said.
Wheat added that increased ability to diagnose whooping cough is also likely contributing to the rising number of cases in the United States.
“Now we have better testing options, so I can do a panel that looks for a variety of different things, and whooping cough is one of them,” he noted. “The numbers have increased, but I also think part of that is because we are detecting it more frequently.”
Still, Blumberg urged parents to take the threat of whooping cough seriously and get their children vaccinated or boosted.
“They’ll say, ‘Whooping cough is just a cough and kids outgrow it,’” Blumberg said. He added: “We need clear and consistent messages about vaccines. “A lot of people have forgotten about them.”
