San Francisco Department of Public Health Update on Tuberculosis Cases at Archbishop Riordan High School

SAN FRANCISCO - The San Francisco Department of Public Health (SFDPH) continues to respond to the tuberculosis (TB) outbreak at Archbishop Riordan High School (ARHS). SFDPH has been working closely with the school and health providers on contact tracing, testing, as well as treatment guidance. San Francisco’s Health Officer reports that the risk to the general public remains low.

As of February 20, 2026, three cases of active TB have been confirmed in the school community. The first case was diagnosed in November 2025, and the second and third case were diagnosed in January 2026. As further testing was conducted, three additional suspected active TB cases were detected. Importantly, all people with confirmed and suspected active TB cases are on treatment and there are currently no contagious cases on campus.

Using a TB clearance process developed under guidance from SFDPH, ARHS has been able to clear 99% of current students and 100% of faculty and on-campus staff from active TB disease in order to safely return to fully on-campus learning.

SFDPH has received a total of 1,261 test results from ARHS students and staff for independent validation. Among these 1,261 individuals, 219 (17%) had a positive TB test. Of those, there is a confirmed total of 204 latent TB cases, and x-ray results to rule out active TB are in process for the remaining individuals with a positive TB test.

About Latent TB

While people with latent TB are not sick or contagious, the infection may develop into active TB — a serious illness — if left undetected and untreated, which is why contact tracing, testing, and treatment efforts are so critical.

“Latent TB is not contagious and the risk to the general public remains low,” said San Francisco Health Officer Dr. Susan Philip. “Contact tracing and testing are critical to identify cases so we can prevent future cases of active TB and empower members of the community to take action and get the treatment they need to protect their long-term health and the health of those around them. The health and well-being of the entire school community, and all residents of San Francisco, continues to be our top priority. We are committed to working closely with the school until this outbreak is resolved.”

To date, there have been no related cases of active TB reported to SFDPH at any school in San Francisco outside of ARHS, and there are no actions currently required outside of what has been communicated to the ARHS community. If there are any actions that people outside the ARHS community — including other schools — should take in relation to this outbreak, SFDPH will notify them directly.

SFDPH TB Response

As outlined below, our investigation and response will continue to be guided by science, available evidence, state and federal guidance, and recognized practices for TB outbreak response.

September 2025

First case is evaluated by a medical provider, reporting 2 weeks of cough.

November 2025

SFDPH receives notification of first case, evaluates patient, diagnoses active TB, and starts patient on treatment. Close contacts are also identified for testing. The first active TB case at ARHS is announced.

December 2025

SFDPH and ARHS notified the school community of required TB testing for students and

staff as a result of close contact testing.

January 2026

SFDPH and ARHS notified the school community of a second and third confirmed active TB case. The required TB testing period for students and staff begins. SFDPH issues a Health Advisory for clinicians

February 2026

SFDPH holds TB information session for local pediatricians. Required TB testing period

for all students and staff ends.

Commitment to the Community

SFDPH continues to provide ongoing medical and public health guidance to reduce the risk of transmission, including recommendations for symptom monitoring, masking indoors, as well

as indoor activity guidance. These measures are being implemented in close consultation with the school and will be updated as new information becomes available.

Throughout this process, SFDPH and ARHS have prioritized clear communication with families and staff, including town halls and regular updates. We will continue to update and work with the school community until the outbreak has been resolved.

To learn more about TB, please visit these resources:

San Francisco Department of Public Health

California Department of Public Health

Centers for Disease Control