The whooping cough outbreak that shook the United States in 2024 and 2025 has not ended. It has moderated from its peak, but the structural conditions that produced it — falling vaccination coverage, a vaccine whose immunity fades faster than public health messaging acknowledges, and a strained public health workforce — remain firmly in place. As of late May 2026, approximately 4,598 cases of pertussis have been documented nationwide, with California alone reporting nearly 700 cases, followed by Washington State at over 328, Ohio at over 280, and Florida at over 262.
These numbers come against a backdrop of catastrophic cyclical surge. In 2024, the United States reported 43,321 cases of whooping cough — the highest annual total in more than a decade. In 2025, that number remained elevated at 28,783 cases. By comparison, there were just 7,063 cases in 2023, meaning the country saw a roughly six-fold increase in a single year. Both 2024 and 2025 were accompanied by confirmed deaths: two infants in Louisiana, a child in Washington State (the first pertussis death in that state since 2011), an adult in Idaho, and others across Kentucky and South Dakota — deaths from a disease that can be prevented by a vaccine available at any pharmacy in the United States.
"Pertussis cases increase in a cyclical fashion driven by waning immunity," Dr. Demetre Daskalakis, former head of the CDC's immunization program, told CBS News. "But the size of the outbreak and the potential for severe outcomes in children who cannot be vaccinated can be mitigated by high coverage and good communication to folks at risk."
The Three Simultaneous Failures Driving the Resurgence
Understanding why whooping cough is killing Americans in 2026 requires understanding three converging problems that public health experts say have been building for years.
The first is declining vaccination coverage. Kindergarten vaccination coverage for whooping cough fell from 95 percent in 2019 to just 92.3 percent by the 2023–24 school year, according to CDC data. While a 2.7 percentage point drop sounds small, the mathematics of herd immunity are unforgiving at the margins. Pertussis has a basic reproduction number (R0) of approximately 12 to 17, meaning each infected person can infect 12 to 17 others in a fully susceptible population. At that level of transmissibility, even modest drops in coverage can produce outsized outbreak amplification. Texas illustrates the policy-specific dimension of this problem: the state reported 1,928 cases in 2024, and by October 2025 had already exceeded 3,500, a trajectory that public health researchers have linked in part to the state's expansion of non-medical vaccine exemptions.
The second problem is waning immunity. The acellular pertussis vaccines used in the United States since the 1990s are safer than the whole-cell vaccines they replaced, but they produce immunity that fades substantially within 3 to 5 years of the last dose. Adolescents who received their Tdap booster at age 11 or 12 are often significantly less protected by high school and college. Adults who received Tdap years ago may have little remaining protection. This creates a structural reservoir of susceptible individuals in every age group — not because people refused vaccination, but because even compliant vaccinators age out of protection.
The third problem is a stretched public health infrastructure. Following the COVID-19 pandemic, public health agencies across the country faced funding cuts, staff departures, and a general depletion of surge capacity. The public health workforce that would normally conduct rapid contact tracing, issue school alerts, and coordinate booster campaigns during a pertussis outbreak is operating with far less capacity than it had five years ago.
Who Is Most at Risk and What the Disease Actually Does
Whooping cough is caused by the bacterium Bordetella pertussis and is transmitted through respiratory droplets when an infected person coughs or sneezes. It earns its common name from the high-pitched inspiratory "whoop" that children produce when trying to breathe after violent coughing paroxysms. In older children and adults, the disease more often presents without the classical whoop — instead causing a persistent, severe cough that can last for weeks to months and is frequently misdiagnosed as bronchitis.
For infants under 6 months of age who have not yet completed their primary vaccination series, whooping cough is a life-threatening emergency. Infants cannot perform the whooping maneuver that creates the recognizable sound; instead, they develop apnea — complete cessation of breathing for 20 seconds or more — a terrifying presentation that is the most common cause of pertussis-related infant hospitalization and death. Infants this young cannot be vaccinated against pertussis; they depend entirely on the immunity of the people around them.
The current recommended schedule includes the DTaP vaccine at 2, 4, 6, and 15 to 18 months, with a booster between 4 and 6 years. A Tdap booster is recommended at age 11 to 12 and once in adulthood. Critically, CDC recommends that pregnant women receive Tdap during the third trimester of every pregnancy — the most effective strategy for protecting newborns, who receive maternal antibodies that provide partial protection before they can be vaccinated themselves. Only approximately 60 percent of pregnant women currently receive this recommendation, leaving roughly 40 percent of newborns without the best available protection at birth.
What You Should Do Right Now
If you have not received a Tdap booster in the last 5 years, talk to your doctor or pharmacist. Tdap is available at most pharmacies without an appointment and is covered by most insurance plans. If you are pregnant or planning to become pregnant, ensure you receive Tdap in your third trimester regardless of prior Tdap history — each pregnancy warrants a new dose because the antibodies you pass to your baby are time-sensitive. If you are a parent, check your child's vaccination records to confirm they are up to date on the recommended DTaP schedule. If anyone in your household develops a cough lasting more than two weeks, particularly with paroxysmal quality, see a physician and ask whether pertussis testing is warranted.
Frequently Asked Questions
Q: How many whooping cough cases have been reported in the United States in 2026 so far?
A: Approximately 4,598 cases as of late May 2026, with California (nearly 700), Washington (328+), Ohio (280+), and Florida (262+) leading all states.
Q: How many Americans died of whooping cough in the recent surge?
A: Multiple deaths have been confirmed during the 2024–2025 surge, including two infants in Louisiana, a child in Washington State (first pertussis death there since 2011), and adults in Idaho and other states.
Q: Why is whooping cough still surging despite vaccines being available?
A: Three converging factors: declining vaccination coverage (kindergarten rates fell to 92.3%), waning immunity from acellular vaccines (which fade within 3–5 years), and a stretched public health infrastructure with reduced contact tracing and outbreak response capacity.
Q: Who is most at risk from whooping cough?
A: Infants under 6 months who cannot yet be fully vaccinated face the highest mortality risk. Adolescents with waning vaccine immunity and unvaccinated adults are the most common source of infections passed to infants.
Q: How can I protect myself and my family right now?
A: Check vaccination status and get Tdap if you have not had one in 5 years. Pregnant women should receive Tdap in every third trimester. Ensure children are on schedule for DTaP vaccinations starting at 2 months.
