Two children have died from whooping cough (pertussis) in the United States in 2026, according to CDC surveillance data — and with the summer peak season now fully underway, the agency is urging parents to recognize the disease's deceptively delayed warning signs before it progresses to its most lethal stage.
According to the CDC's pertussis surveillance data through week 21 of 2026 (late May), the United States has confirmed 4,598 pertussis cases nationally. The states with the highest case burdens include California (700+ cases), Washington (328+), Ohio (280+), and Florida (262+). The CDC notes that pertussis activity is still being captured and that the actual number of cases is likely significantly higher, as many mild and moderate cases go undiagnosed or unreported — pertussis is notoriously difficult to diagnose by clinical presentation alone, particularly in older children and adults who have been previously vaccinated.
The two child deaths in 2026, while representing a small fraction of total cases, follow a well-documented epidemiological pattern: deaths from pertussis are almost exclusively concentrated in infants under 12 months of age who are too young to have received the full three-dose primary DTaP series. The deaths serve as the most extreme outcome of a disease that also produces significant non-fatal morbidity, including pneumonia, rib fractures from coughing paroxysms, brief resolved unexplained events (BRUEs) in infants, and seizures.
What Whooping Cough Is — and Why It's Called the "100-Day Cough"
Pertussis is caused by Bordetella pertussis, a gram-negative bacterium that adheres to the cilia lining the respiratory tract and produces toxins that damage those cilia and trigger the body's hypersensitive cough response. According to the CDC's clinical description, the disease progresses through three stages that are important for parents to understand:
Stage 1 — Catarrhal Stage (1–2 weeks). The most contagious stage, and the one least likely to be recognized as pertussis. Symptoms include a runny nose, mild cough, and low-grade fever, indistinguishable from a common cold. During this stage, a person with pertussis can transmit the disease to unvaccinated contacts with an R0 (basic reproduction number) estimated at 12–17, among the highest of any vaccine-preventable disease.
Stage 2 — Paroxysmal Stage (1–6 weeks). The characteristic — and diagnostically recognizable — stage: severe, uncontrollable coughing fits (paroxysms) lasting up to 1 minute, often followed by the distinctive "whoop" sound that gives the disease its common name, caused by the patient's desperate inhalation after the paroxysm. Vomiting after coughing episodes is common. Cyanosis (turning blue) during paroxysms can occur, particularly in infants. Infants under 6 months may not produce the "whoop" — they may instead show apnea (periods without breathing), which is medically emergent.
Stage 3 — Convalescent Stage (weeks to months). Gradual recovery, but coughing paroxysms can persist or recur with respiratory triggers for 2–3 months — hence the "100-day cough" designation.
| Whooping Cough Surveillance Data — 2026 (through late May) | Detail |
| Total confirmed national cases | 4,598 |
| Child deaths in 2026 | 2 |
| Deaths demographic | Almost exclusively infants under 12 months (insufficient vaccination) |
| Leading states by case count | California (700+), Washington (328+), Ohio (280+), Florida (262+) |
| Season | Summer peak (highest transmission June–September annually) |
| Most contagious stage | Catarrhal (stage 1) — looks like a cold |
| Most dangerous group | Infants under 6 months (too young for full DTaP series) |
| R0 (basic reproduction number) | 12–17 (among highest of vaccine-preventable diseases) |
| Primary vaccine | DTaP (infant series at 2, 4, 6 months, and boosters at 15–18 months and 4–6 years) |
| Adult booster | Tdap (one-time; recommended for adults who have never received it, especially pregnant women and new parents) |
| Infant protection strategy | Maternal Tdap during pregnancy (28–36 weeks) + "cocooning" (vaccinating all household contacts) |
| Treatment | Azithromycin (most common); clarithromycin; erythromycin — most effective when started in catarrhal stage |
Who Is at Highest Risk — and Why Summer Amplifies It
Every year, pertussis follows a seasonal pattern with peaks in summer and early fall. Summer gatherings — Fourth of July cookouts, family reunions, outdoor events, travel — bring vaccinated and unvaccinated individuals together across age groups, providing enhanced transmission opportunities for a bacteria that requires no special environmental conditions, only close contact between a contagious person and a susceptible one.
Infants under 12 months are the highest-risk population by every clinical measure. The primary DTaP series requires three doses at ages 2 months, 4 months, and 6 months, followed by booster doses at 15–18 months and 4–6 years. A 2-month-old infant at a July 4th gathering with an undiagnosed coughing adult family member who received their last pertussis vaccine in childhood has no meaningful protection. The infant's risk of severe disease, hospitalization, and death is orders of magnitude higher than any other age group.
Pregnant women — and through them, their newborns. The CDC recommends Tdap vaccination between 28 and 36 weeks of each pregnancy. Maternal antibodies generated after vaccination cross the placenta and provide passive immunity to the newborn in the weeks before the infant is old enough to receive their first DTaP dose. This is currently the most effective single intervention for preventing infant pertussis deaths — and it requires a specific, renewed vaccination with each pregnancy.
Adults and adolescents with waning immunity. Pertussis vaccine immunity wanes significantly over 5–10 years — meaning adults who received their last pertussis-containing vaccine as children may have substantially reduced protection. Tdap (the adult-formulation tetanus-diphtheria-acellular pertussis vaccine) is recommended as a one-time booster for adults who have never received it, and additionally with each pregnancy. Adults with waning immunity are the primary transmission vector to infants — they carry and spread pertussis before recognizing that their persistent cough is anything other than a seasonal illness.
What the Warning Signs Are — and When to Act
For parents, the most critical recognition challenge is identifying pertussis in its early, most treatable stage rather than waiting for the characteristic "whoop" that may come too late — particularly in infants.
Call your pediatrician immediately if your infant under 12 months develops:
- A runny nose or cough that is accompanied by any period without breathing (apnea)
- Turning blue or pale during a coughing episode
- Coughing fits so severe they cause vomiting
- A coughing fit followed by a high-pitched sound on inhalation (the "whoop")
- Significant distress or lethargy after coughing episodes
For older children and adults, consult your healthcare provider if you develop:
- A persistent cough lasting more than 2–3 weeks that produces severe coughing fits
- Coughing fits that end with a whooping sound on inhalation
- Vomiting after coughing
- Any cough in an unvaccinated or partially vaccinated household with a young infant
Pertussis is treated with antibiotics (most commonly azithromycin). Treatment begun in the catarrhal stage — before severe paroxysms develop — dramatically reduces disease severity and transmission. Once the paroxysmal stage is fully established, antibiotics have less impact on symptom severity but still reduce transmission to others.
Frequently Asked Questions
How many whooping cough cases have been confirmed in 2026?
As of CDC surveillance through week 21 of 2026 (late May), 4,598 pertussis cases have been confirmed nationally. The leading states by case count are California (700+), Washington (328+), Ohio (280+), and Florida (262+). Summer peak season is now fully underway, and case counts typically continue rising through September.
How many children have died from whooping cough in 2026?
Two child deaths have been confirmed in 2026. Deaths from pertussis are almost exclusively concentrated in infants under 12 months who have not yet completed the primary DTaP vaccination series.
What are the first signs of whooping cough?
The first stage (catarrhal stage, 1–2 weeks) looks exactly like a common cold: runny nose, mild cough, low-grade fever. This is also the most contagious stage. The characteristic coughing fits and "whoop" sound develop in the second (paroxysmal) stage, typically 1–2 weeks after symptoms begin. Infants under 6 months may not produce the whoop — instead showing apnea (stopped breathing), which is a medical emergency.
Who should get vaccinated against whooping cough?
Infants receive DTaP at 2, 4, and 6 months and boosters at 15–18 months and 4–6 years. All pregnant women should receive Tdap between 28–36 weeks of each pregnancy to protect their newborns. All adults who have never received Tdap should get one dose. New parents, grandparents, and anyone who will be in close contact with a newborn should ensure they are currently vaccinated.
What should I do if I think my infant has whooping cough?
Call your pediatrician or go to the emergency room immediately — do not wait. Any infant under 12 months with coughing fits, apnea, cyanosis, or severe respiratory distress needs urgent evaluation. Pertussis can be rapidly fatal in young infants.
