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.
