Whooping cough is on a trajectory that public health officials are watching with alarm. CDC surveillance data through Week 21 of 2026 confirm 4,598 cases of pertussis confirmed nationally — with summer barely underway, and case counts historically continuing to rise through September.
Two children have died from whooping cough in 2026. Deaths from pertussis are almost exclusively concentrated in infants under 12 months who have not yet completed the primary DTaP vaccination series — the age group most biologically vulnerable and the age group that depends on the immunity of vaccinated people around them for protection.
The states driving the largest case burdens are California (700+ cases), Washington (328+), Ohio (280+), and Florida (262+), according to MedicalDaily.com's analysis of CDC data. Oregon has also surpassed 200 cases, making five states each reporting more than 200 cases to date in 2026. Johns Hopkins Bloomberg School of Public Health's International Vaccine Access Center (IVAC) has published a direct assessment: "insufficient immunization coverage" is a primary driver of the current increase.
The Vaccine Gap Behind the Deaths
The most direct explanation for the 2026 surge is in the vaccination data. IVAC's analysis found that of children under 6 years who contracted whooping cough in 2025 — the year that set a 13-year case record in the United States with 28,783 cases — only 1 in 5 had completed their primary series of three or more doses of the diphtheria, tetanus, and pertussis (DTaP) vaccine.
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 cited in MedicalDaily reporting. While a 2.7 percentage point drop sounds small, the mathematics of herd immunity are unforgiving at those margins. Whooping cough 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. Small gaps in vaccination coverage translate directly into sustained community transmission.
"Pertussis cases increase in a cyclical fashion driven by waning immunity," said Dr. Demetre Daskalakis, former head of the CDC's immunization program, in comments to 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."
| Pertussis Surveillance Data 2026 | Detail |
| Total confirmed U.S. cases (through Week 21) | 4,598 |
| Confirmed child deaths | 2 |
| California | 700+ cases |
| Washington | 328+ cases |
| Ohio | 280+ cases |
| Florida | 262+ cases |
| Children under 6 with complete vaccine series (2025 cases) | Only 1 in 5 |
| Kindergarten vaccination rate (2023–24) | 92.3% (down from 95% in 2019) |
| Historical peak (2024) | 43,321 cases |
| 2025 cases | 28,783 |
| When cases typically peak | Summer through September |
Who Is Most at Risk — and What Parents Need to Do
Infants under 12 months are the most dangerous target for whooping cough. Their immune systems are immature, and many have not yet completed the primary DTaP vaccination series (given at 2, 4, and 6 months), leaving them unprotected during the most vulnerable window. Most pertussis-related deaths occur in this age group.
The disease progresses through three stages that make early diagnosis difficult. The first stage — the catarrhal stage, lasting one to two weeks — is the most contagious and looks exactly like a common cold: runny nose, mild cough, and low-grade fever. Parents, caregivers, and physicians rarely identify pertussis at this stage. The diagnostic window arrives in the second stage — the paroxysmal stage — when severe, uncontrollable coughing fits develop, often followed by the characteristic "whooping" sound of the desperate inhalation after the paroxysm. The cough can last for weeks or months, even after the infection resolves.
The CDC recommends that clinicians consider pertussis in any patient with a persistent cough, particularly infants and caregivers of newborns. Early antibiotic treatment can shorten the contagious period and may reduce symptom severity. Families are encouraged to make sure children, teenagers, and adults are up to date on their DTaP and Tdap vaccines, and to keep sick visitors away from newborns. Pregnant women should receive a Tdap dose during every pregnancy — ideally between 27 and 36 weeks — to pass protective antibodies to their newborns before birth.
Frequently Asked Questions
How many whooping cough cases are there in 2026?
CDC surveillance data through Week 21 of 2026 confirm 4,598 confirmed pertussis cases nationally, with California (700+), Washington (328+), Ohio (280+), Florida (262+), and Oregon (200+) leading in case counts. Summer is peak season for whooping cough, and cases typically continue rising through September.
Which children are most at risk from whooping cough?
Infants under 12 months, especially those who have not yet completed the three-dose primary DTaP series, face the highest risk of severe illness and death from pertussis. Of children under 6 who contracted whooping cough in 2025, only 1 in 5 had completed their primary vaccine series.
What are the symptoms of whooping cough?
Whooping cough begins with cold-like symptoms — runny nose, mild cough, low-grade fever — during the most contagious first stage (1–2 weeks). The second stage brings severe, prolonged coughing fits followed by a high-pitched "whoop" when the patient inhales desperately. Infants may not make the whooping sound and instead may turn blue, gasp, or briefly stop breathing.
Are the DTaP and Tdap vaccines effective?
Yes. The DTaP and Tdap vaccines are the most effective tools available for preventing whooping cough. Children should receive five doses between the ages of 2 months and 4 to 6 years. Immunity wanes over time, so adults and adolescents need Tdap boosters. Pregnant women should receive Tdap during every pregnancy to protect newborns.
How can I protect my infant from whooping cough?
Get vaccinated yourself,
and ensure all household members and frequent visitors are current on their Tdap vaccine. Protect your newborn from contact with anyone who has a cold or cough. If you are pregnant, receive the Tdap vaccine between 27 and 36 weeks of pregnancy to pass protective antibodies to your baby before birth. Contact your pediatrician immediately if your infant develops cold-like symptoms, particularly a persistent cough.
