The Centers for Disease Control and Prevention reported Thursday that whooping cough cases for this time of year hit their highest level in a decade. With 18,506 cases reported so far in 2024, the total marks the most cases recorded since 2014, when cases topped 21,800.

Health officials noted that an increase was somewhat expected, as whooping cough tends to peak every three to five years. The current numbers suggest a return to pre-pandemic levels when whooping cough and other contagious illnesses were more prevalent.

While whooping cough, also known as pertussis, is often associated with infants and young children, it affects individuals of all ages. A study published last year in Infectious Diseases and Therapy found that adults aged 50 and older who were diagnosed with pertussis experienced significant increases in healthcare resource utilization and direct medical costs.

This year’s outbreaks are most notably impacting older children and teens. Justin Frederick, deputy director of the health department in Douglas County, Nebraska, told the Associated Press that nearly all cases in his area are among school-aged children and teenagers.

Vaccination rates have shown a concerning decline. The CDC reported that kindergarten vaccination rates dipped last year, with vaccine exemptions at an all-time high. In Wisconsin, about 86% of kindergartners received the whooping cough vaccine, compared with more than 92% nationally.

Whooping cough typically begins with cold-like symptoms before developing into a prolonged cough. It’s treated with antibiotics and can be particularly serious for infants. The vaccine, introduced in the 1950s, is now part of routine childhood vaccinations and is recommended for adults every 10 years.

Health experts stress the importance of early testing and treatment with antibiotics to prevent the spread of the disease. They also emphasize that safe and effective vaccines are available for prevention.