TB Outbreak at San Francisco High School: A Sign of Rising Concerns?
A recent outbreak of tuberculosis (TB) at Archbishop Riordan High School in San Francisco has brought renewed attention to the disease, with health officials announcing 204 cases of latent TB among students and staff. While the immediate risk to the general public remains low, the incident raises questions about potential trends in TB transmission and public health preparedness.
Understanding Latent vs. Active TB
It’s crucial to differentiate between latent and active TB. Latent TB means a person has been infected with the bacteria, but the immune system is keeping it under control. Individuals with latent TB don’t feel sick and cannot spread the infection. However, without treatment, there’s a risk – around 5% over a lifetime – that the latent infection can progress to active TB disease, particularly in those with weakened immune systems. Active TB is contagious and can cause serious illness.
The Riordan Outbreak: What the Numbers Tell Us
The San Francisco Department of Public Health (SFDPH) began investigating after identifying three cases of active TB at the school since November 2025. Subsequent testing of students and staff revealed 219 positive results for tuberculosis, with 204 confirmed as latent TB – approximately 16% of those tested. Chest X-rays are being conducted to rule out active disease in the remaining positive cases.
According to Dr. George Rutherford, a pediatrician and infectious disease specialist at UCSF, the proportion of latent infections is significant. He noted that the rate is higher than typically seen in the general population, where latent TB prevalence is around 6% in California and approximately 10% globally.
Why is TB Re-emerging?
While TB was once a leading cause of death in the United States, it had largely been brought under control. However, cases have been on the rise statewide since 2023, prompting concern among public health officials. Several factors may be contributing to this resurgence.
- Disruptions to Healthcare: The COVID-19 pandemic led to disruptions in routine healthcare services, including TB screening and treatment.
- Social Determinants of Health: Poverty, overcrowding and limited access to healthcare can increase the risk of TB transmission.
- Increased Travel: International travel can expose individuals to TB from regions with higher prevalence rates.
- Weakened Immunity: Conditions like HIV and certain medications can weaken the immune system, making individuals more susceptible to active TB.
School Settings and TB Transmission
Schools can be settings where TB transmission occurs, particularly in enclosed spaces. Activities like choir or other forceful exhalation exercises may increase the risk of airborne spread. The Riordan outbreak prompted a temporary shift to hybrid learning while a TB clearance protocol was implemented, allowing the school to return to in-person instruction within three weeks.
Public Health Response and Future Preparedness
The SFDPH’s response to the Riordan outbreak has been described as thorough and appropriate. Contact tracing, testing, and treatment guidance have been provided to those affected. The incident underscores the importance of robust TB screening, ventilation, and clear outbreak protocols in schools and other community settings.
As of February 20, 2026, three confirmed cases of active TB and three suspected cases have been identified within the school community, all of whom are currently receiving treatment. The health department reports that You’ll see no currently contagious cases on campus.
FAQ
Q: Is latent TB contagious?
A: No, latent TB is not contagious. You cannot spread it to others.
Q: What are the symptoms of active TB?
A: Symptoms include a persistent cough, fever, night sweats, and weight loss.
Q: How is TB treated?
A: Active TB is treated with antibiotics. Latent TB infection is also often treated with antibiotics to prevent it from progressing to active disease.
Q: What is the risk of developing active TB from a latent infection?
A: About 5% of people with latent TB will develop active TB disease over their lifetime. The risk is higher for those with weakened immune systems.
This outbreak serves as a critical reminder of the ongoing need for vigilance and investment in public health infrastructure to prevent and control the spread of tuberculosis. Continued monitoring, research, and proactive measures are essential to protect communities from this potentially serious disease.
