Tuberculosis Screening at San Francisco School Finds 204 Latent Cases

The San Francisco Department of Public Health announced on February 20, 2026, that hundreds of students and staff at Archbishop Riordan High School underwent tuberculosis testing following the identification of active cases in the school community.

Health officials stated that 204 cases of latent tuberculosis were found among those tested at the school. The department also confirmed that three individuals were diagnosed with active tuberculosis between November 2025 and January 2026, with three additional suspected active cases under evaluation at the time of the announcement.

Testing at the school included 1,261 students and staff, with 219 people testing positive for tuberculosis. Of those, 204 were confirmed as latent infections, which accounts for about 16% of those tested. The department reported that chest X-rays were being conducted to determine whether any of the remaining positive cases involved active disease.

According to the San Francisco Department of Public Health, the initial active tuberculosis case was identified in November 2025. This prompted contact tracing and expanded testing efforts throughout the school. No related active tuberculosis cases were reported at other schools in San Francisco as of the announcement date.

What the numbers show

• 1,261 students and staff were tested for tuberculosis
• 219 tested positive, with 204 confirmed as latent TB cases
• Three active TB cases were identified at the school

After the school closed temporarily to address the outbreak, a tuberculosis clearance protocol was implemented with guidance from public health authorities. The school was able to clear 99% of students and all faculty and staff to return to in-person classes three weeks after the closure.

The department stated that the risk to the general public from the outbreak remains low. Officials continued to monitor the situation and conduct additional evaluations as needed to prevent further spread within the school community.

Background information from public health sources indicates that the estimated prevalence of latent tuberculosis in California is about 6%, while the global rate is approximately 10%. Without treatment, around 5% of people with latent tuberculosis may develop active disease over their lifetime, with the risk higher among immunocompromised individuals.

No additional active tuberculosis cases connected to this incident have been reported in other San Francisco schools, according to the San Francisco Department of Public Health. The department continued to provide updates and guidance as the situation developed.

* This article is based on publicly available information at the time of writing.