Whooping cough cases are climbing at the fastest pace in years as students across America return to school, U.S. health officials reported Thursday.

In figures published by the U.S. Centers for Disease Control and Prevention, a total of 291 cases were reported for the week ending Sept. 14. New York logged the most cases of any state, with 44 infections. Oklahoma followed closely behind with 40 cases, while Ohio has reported 39 illnesses and Pennsylvania has reported 38 infections.

Not since 2015 have numbers that high been reported for Bordatella pertussis infections, when the United States was coming off a resurgence of whooping cough cases that peaked the year before, the data showed.

So far this year, 14,569 cases have been reported, more than four times higher than the number of infections reported by this time last year, the CDC reported.

U.S. health officials have warned for months about a resurgence in breakthrough infections in older children and adults, even though unvaccinated young children and newborns of unvaccinated moms remain the most vulnerable to both infection and severe disease, CBS News reported.

Why are there so many breakthrough infections?

For the past few decades, whooping cough cases have continued to climb because the United States switched to pertussis vaccines that have fewer side effects but aren’t as powerful or long-lasting as older shots, CBS News reported.

In Pennsylvania, which has witnessed one of the country’s largest pertussis outbreaks this year, health officials noted that high school students have fueled that surge in cases.

“Historically, pertussis was primarily considered a childhood infection; however, there has been an increasing awareness of cases and hospitalizations occurring in older adults,” the Pennsylvania Department of Health said in an health alert. “This is likely due to a multitude of factors, including waning vaccine protection and the lack of timely recognition and testing by adult providers leading to more severe infections, co-infections and hospitalizations in older adults.”

A similar scenario has unfolded in New York, where 40% of cases outside of New York City have been in teens ages 15 to 19, CBS News reported. 

In Oklahoma, which has seen one of the biggest jumps in cases of any state in recent weeks, cases have been seen in people as old as 86, the Oklahoma State Department of Health told CBS News.

The resurgence arrives as the U.S. Food and Drug Administration is weighing speeding up the development of more effective pertussis shots: An FDA advisory panel plans to meet Friday to discuss potential pertussis booster vaccine trials for adults.

The CDC already recommends a number of pertussis shots for children and adults, including boosters of the Tdap vaccine — which contains antigens designed to protect against pertussis — for all adults every 10 years. 

While whooping cough cases are clearly on the rise, health officials noted that it is not time to panic.

“Despite the resurgence of pertussis, current rates of disease are very low relative to the rates reported during the pre-vaccine era,” FDA officials wrote in briefing documents prepared for the advisory panel.

More information

The CDC has more on whooping cough.

SOURCES: U.S. Centers for Disease Control and Prevention, news release, Sept. 19, 2024; CBS News

Source: HealthDay