Whooping cough cases have quintupled. These states have it worst.

(NEXSTAR) – Pertussis — a disease commonly referred to as whooping cough — is spreading quickly, the Centers for Disease Control and Prevention warns. The U.S. has seen five times more cases in 2024 than we did at this time last year.

As of Nov. 9, which marks the latest data available from the CDC, there were more than 23,500 cases of whooping cough reported so far this year. That's far and above the roughly 5,000 cases confirmed in all of 2023.

Health officials warn the case count will continue to rise if people aren't careful. The disease is highly contagious and can spread quickly through schools, childcare centers and over large areas. It spreads easily person-to-person as people cough, and sickened people can be contagious for weeks.

Experts believe the 2024 surge in cases may be in part because of missed vaccinations during the COVID-19 pandemic. Widespread masking in 2020 and 2021 also helped prevent spreading of the bacteria that causes pertussis. Now, the disease is back with a vengeance, and we're seeing more cases than we did in 2019.

As of early November, the disease seems to be spreading fastest on the East Coast. Pennsylvania has the most cases of any state, with 2,523. New York is close behind with 2,142.

Nevada, Connecticut, New Hampshire, West Virginia and D.C. have reported the fewest cases to the CDC. Wyoming reported no cases of whooping cough.

What are the symptoms of pertussis/whooping cough?

As its nickname suggests, the disease’s main symptom is a bad cough, followed by a “high-pitched intake of breath that sounds like ‘whoop,'” the Mayo Clinic explains.

The onset of symptoms can look a lot like the common cold. People report having congestion, a runny nose, watery eyes, fever, and a cough.

But if the symptoms are persistent, and start to worsen after a week or two, it may be whooping cough.

“Thick mucus accumulates inside your airways, causing uncontrollable coughing,” the Mayo Clinic says.

Young babies, who are especially vulnerable to complications from pertussis, may not cough at all. “Instead, they may have apnea (life-threatening pauses in breathing). The apnea may cause cyanosis (to turn blue) or they may struggle to breathe,” the CDC says.

How is whooping cough treated?

While many people can recover on their own, whooping cough can be treated with the help of antibiotics.

Vaccines can also help prevent getting sick with pertussis in the first place. While the vaccines are highly effective, they wear off, so the CDC recommends making sure you’re up to date.

Babies need to be vaccinated at 2 months, 4 months and 6 months. Kids need two booster shots – one between the ages of 15 and 18 months, the other between 4 and 6 years old. Preteens should get a booster between 11 and 12 years old, too. The CDC also recommends adults get vaccinated if they’ve never had a dose.