After two years with spikes in activity, the Americas region is reporting a slight decline in confirmed cases of pertussis, or whopping cough, in 2025, according to the newest epidemiological update from the Pan American Health Organization (PAHO).
In 2025, the countries of the region reported 46,870 cases, down from 66,184 cases in 2024. There was a sharp, COVID-19 pandemic-related decline in 2021-2022, with just 3,284 cases reported, followed by 11,202 cases in 2023.
US has the most cases
The United States led the region in pertussis cases last year, with 28,783 confirmed and probable cases of pertussis reported, including 16 deaths. So far this year the country has reported 2,355 confirmed cases of pertussis, including one death. Washington state had the most cases in 2025.
“Cases peaked nationally in November 2024 and remained elevated throughout 2025 compared with data from before the COVID-19 pandemic,” PAHO said.
The most affected age groups were those aged 11 to 19 years, accounting for 27% of cases, and those aged one to 6 years, accounting for 26% of cases. Deaths in the United States primarily occurred in infants under one year.
By comparison, the country with the second-most pertussis cases reported in 2025 was Chile, with 3,387 cases, including six deaths.
PAHO said vaccination against pertussis remains important, and said booster doses are required to maintain immunity levels against the disease.