California has recorded its highest number of tuberculosis (TB) infections in more than a decade, according to a new report. Data from the California Department of Public Health shows the state registered 2,150 cases in 2025, marking a 12-year high and a 2% increase from the previous year. The state also had a TB infection rate nearly double the national average, with 5.4 cases per 100,000 people compared to the US average of 3 per 100,000.
Rising Deaths and Infection Trends
Approximately 13% of TB patients—279 individuals—died from the disease last year. Of these fatalities, 24% did not receive treatment. Health officials noted that about 83% of cases resulted from latent infections progressing to active disease, suggesting many could have been prevented with testing and treatment. Seven percent of cases involved people who arrived in the state already infected, while 10% stemmed from recent transmission.
California’s TB cases have remained relatively stable at around 2,000 to 2,100 annually since 2013, though numbers dipped during the COVID-19 pandemic. The current tally represents a 60% drop from the 1992 peak of 5,300 cases, which was reduced through major public health efforts.
Outbreak at Private School Raises Alarm
Last week, officials in San Francisco raised concerns over a TB outbreak at an exclusive $30,000-per-year private school, exposing over 241 individuals to the disease. Seven pupils have active infections, and 241 have latent infections. Dr. Monica Gandhi, an infectious disease expert at the University of California San Francisco, described it as a significant outbreak, noting that a 20% latent TB rate in a school population is unusual in the US and more typical of low-income countries.
Expert Commentary on Contributing Factors
Experts attribute the surge to lingering distrust of healthcare stemming from the COVID-19 pandemic, leading people to delay treatment until TB progresses to an active stage. Dr. Martin Willis, former public health officer for Marin County, told SFGate that TB thrives when individuals lose access to healthcare, allowing latent disease to go undetected and untreated.
National Context
Nationally, the US recorded over 10,000 TB cases in 2024, the highest since 2011, with infections rising in 80% of states. Provisional data for 2025 shows a 1% decline but cases remain above 2011 levels. TB remains a serious threat, killing around 500 Americans annually and 1.2 million people worldwide each year.
About Tuberculosis
TB is caused by the bacterium Mycobacterium tuberculosis, spread through coughs and sneezes. Without treatment, over 50% of patients die. Early symptoms include a persistent cough and coughing up blood; later stages can involve breathing difficulties and lung damage. Antibiotics are the standard treatment, though drug-resistant strains are emerging. A vaccine exists but is not routinely offered in the US due to historically low case numbers.
