'This is a big outbreak': Nearly 1 in 5 affected by TB at SF school
SFGATE • • health
Key Points:
- Nearly 18% of tested students and staff at Archbishop Riordan High School in San Francisco were diagnosed with either latent or active tuberculosis during an outbreak that began in November, with 7 active and 241 latent cases reported.
- Approximately 96% of the school community was tested, and new testing starting today is limited to those recently exposed or part of a small group with new latent TB cases found in March, as mass testing is no longer required.
- The San Francisco Department of Public Health noted a strong reduction in transmission after March testing, and 95% of latent TB cases are undergoing or have completed treatment, while all active cases are being treated.
- Tuberculosis cases in California reached a 12-year high in 2025, with the state reporting a higher infection rate than the national average, highlighting ongoing public health challenges.
- Experts emphasized that the outbreak is significant, as TB clusters are defined by four or more active cases, and the high latent TB rate at the school is unusual for the U.S., typically seen in low-income countries.
