Whooping Cough Cases Surge Again Across the U.S.

Doctors throughout the United States are bracing for a difficult year as whooping cough—also known as pertussis—continues to rise. Preliminary data shows that, so far in 2025, there have been 8,485 reported cases nationwide. Centers for Disease Control and Prevention (CDC). That figure is double the number of cases recorded at this point in 2024, highlighting a sharp and concerning upward trend.

The rise in pertussis cases is not entirely unexpected. Experts anticipated a resurgence following the COVID-19 pandemic, when widespread use of face masks, social distancing, and other preventive measures significantly reduced the transmission of many respiratory illnesses. But those safety protocols also meant fewer people were exposed to common pathogens, leading to lower levels of natural immunity in the population.

Pertussis, which is highly contagious and spreads through airborne respiratory droplets, tends to follow a cyclical pattern, typically peaking every two to five years. However, the recent surge is also being linked to declining vaccination rates — a troubling shift that has left many healthcare professionals alarmed.

“This trend isn’t just part of the usual rise and fall we expect with this disease,” said Dr. Ericka Hayes, senior medical director for infection prevention and control at the Children’s Hospital of Philadelphia. “There’s unfortunately been increasing anti-vaccine sentiment in the United States, and that’s putting our communities at greater risk.”

According to recent CDC data, vaccination rates among U.S. kindergarteners have declined, while vaccine exemptions have climbed to record levels. When coverage falls below the critical 95% threshold, communities lose what's known as "herd immunity" — the shared protection that helps prevent the spread of infectious diseases and keeps outbreaks under control.

“Without that critical level of immunization, we’re leaving too many people exposed,” Dr. Hayes added. “And unfortunately, the recovery in vaccination rates post-COVID hasn’t been nearly as fast or widespread as we’d hoped.”

Whooping cough often begins with mild symptoms that resemble a common cold: runny nose, mild cough, and low-grade fever. But the illness quickly escalates into severe coughing fits, often followed by a high-pitched “whoop” sound as the person gasps for breath. These symptoms can be especially dangerous for infants, who are at the highest risk for serious complications or death.

In the past six months alone, the disease has claimed the lives of two infants in Louisiana and a 5-year-old child in Washington state. These tragedies underscore the critical importance of timely vaccination, especially for the youngest members of the population who may not yet have completed their vaccine schedule.

The pertussis vaccine is typically administered in a series of doses at two, four, and six months of age, with booster shots recommended later in childhood and again every ten years for adults. Pregnant women are also urged to receive the vaccine during each pregnancy to provide their newborns with early protection through maternal antibodies. However, uptake among expecting mothers remains worryingly low.

“We’re just not seeing enough pregnant women getting vaccinated,” Dr. Hayes said. “It’s one of the most important steps they can take to protect their babies, especially in those vulnerable early months of life.”

Certain states are experiencing sharper spikes than others. Pennsylvania, which was hit hard by pertussis last year, has already recorded 207 cases in 2025. According to Neil Ruhland, a spokesperson for the Pennsylvania Department of Health, the majority of these cases are emerging in urban centers like Philadelphia and Pittsburgh, as well as in middle and high school populations.

He noted that 94.6% of kindergarteners in the state are vaccinated — just under the threshold needed for herd immunity. “We’re doing okay overall,” Ruhland said, “but even small gaps in vaccination coverage can lead to outbreaks, especially in densely populated areas.”

In Michigan, health officials are also keeping a close eye on pertussis trends. The state has recorded 516 cases so far this year, with the majority affecting children aged 5 to 17. In 2024, Michigan saw a total of 2,081 cases, and officials expect similar numbers this year.

Dr. Natasha Bagdasarian, Michigan’s chief medical executive, emphasized that vaccine coverage varies widely between counties. “Some schools are reporting vaccination rates as low as 30%, and that’s deeply concerning,” she said. “These pockets of under-vaccinated populations are extremely vulnerable to outbreaks — not just of pertussis, but of other vaccine-preventable illnesses like measles.”

As measles resurfaces in multiple areas, public health departments are feeling the strain. “In 2025, we’re being asked to do more with fewer resources,” said Dr. Bagdasarian. “Although we’re keeping a close watch on pertussis, a significant portion of our efforts is currently focused on responding to measles outbreaks and carrying out contact tracing.

”As public health experts work to contain these surges, they continue to stress the importance of vaccination — not only for individual protection but for the health and safety of entire communities.