Pertussis Snapshot
The Pertussis Snapshot provides quarterly pertussis surveillance data from 2021-2026 in California. The case counts shown are preliminary and may change after final review. Total counts for all figures and tables include cases for the entire year. Refer to "About the Data" for more details about the pertussis case data presented in the dashboard. Data highlights are provided with the dashboard, and you can download the data as an Excel workbook for your own analysis.
About the Data (PDF) | Download the Data (Excel)
Data Highlights
Between January 1 and March 31, 2026 there were 471 cases of pertussis reported in California, compared to 694 cases in the same time period in 2025. Of these, 22 cases (5%) were in infants under 4 months of age, a 37% decrease in this age group compared to quarter 1 in 2025. Twenty cases under age 18 years were hospitalized, of which 18 (90%) were unvaccinated. Elevated pertussis activity has been reported in the South Bay Area, although the Bay Area region as a whole has not experienced an increase compared to quarter 1 in 2025.