Cases of whooping cough, also known as pertussis, are increasing across the United States in 2025 and may surpass the high case counts seen in 2024. According to data from the U.S. Centers for Disease Control and Prevention (CDC), there have been more than 20,000 cases reported nationwide as of early September this year, compared to 19,302 during the same period last year. In total, 35,435 cases were documented in 2024—five times higher than in 2023.
Health officials have noted a noticeable rise in pertussis cases in parts of Colorado since students returned to school. The disease is particularly dangerous for newborns, pregnant women, health care workers, and immunocompromised adults.
Lauren Bryan, infection prevention program manager at UCHealth Yampa Valley Medical Center in Steamboat Springs, emphasized the importance of vaccination: “The old saying ‘An ounce of prevention is worth a pound of cure’ is so true when it comes to protecting yourself and others,” Bryan said.
“Many people minimize the impact of vaccine-preventable illnesses like pertussis, but they can be devastating to others, especially the very young, the very old and people who are immunocompromised,” she said.
“Whooping cough is incredibly transmissible but very preventable if children are vaccinated,” Bryan added. “We saw declines in the state from 2013 to 2021, but sadly, that trend is now going the wrong way.”
Pertussis is caused by Bordetella pertussis bacteria that spread through airborne droplets. These bacteria attach to cilia lining the respiratory tract and release toxins that damage airway cells. Severe complications are common with pertussis; about one in three babies with the illness requires hospitalization.
The CDC reports that while whooping cough infections dropped significantly during COVID-19 pandemic precautions—from over 18,000 cases in 2019 down to just over 2,000 cases in 2021—numbers have risen sharply since then. Large states such as New York and California recorded high numbers of infections last year. Less-populated states including Idaho, Washington and Oregon each reported more than 1,000 cases.
This year’s worst outbreaks are concentrated on the West Coast—in Washington, Oregon and California—and also affect Midwestern states such as Ohio, Michigan, Illinois and Minnesota as well as North Carolina and Arizona.
Pertussis poses significant risks for infants under two months old who are not yet eligible for vaccination; about 70 percent of deaths occur among this age group. Vaccination remains key for protection: DTaP vaccines are given to children starting at two months old through a five-dose series ending between ages four and six years. Adolescents receive a Tdap booster at ages eleven or twelve; adults need a booster every ten years.
Bryan noted that even vaccinated individuals can contract pertussis but tend to experience less severe illness: “No one wants to infect and potentially cause harm to a baby,” she said.
For those infected or exposed to pertussis early on, antibiotics can reduce symptoms or prevent illness from developing further. However, once airway cilia are damaged by bacterial toxins antibiotics will not shorten illness duration.
Public health guidance includes staying home when sick and frequent handwashing; caregivers should ensure vaccinations remain current especially if caring for vulnerable populations such as infants or older adults.
