Rising TB Infections in California
California has recorded its highest number of tuberculosis (TB) infections in over a decade, according to recent data. The state reported 2,150 cases in 2025, the highest since 2013, and a two percent increase compared to the previous year. This marks a significant rise in cases, with California having the most infections in the nation and a TB infection rate nearly double the national average.
In 2024, the United States recorded more than 10,000 TB cases, the highest since 2011. During that year, infections rose in 80 percent of US states. Experts have linked the surge in cases to a growing distrust of medical professionals, which has been exacerbated by the pandemic. This has led to fewer people seeking treatment until the disease reaches an advanced stage, when it becomes active and more difficult to treat.
A Growing Concern in San Francisco
Last week, officials in California raised concerns about a TB outbreak at an exclusive private school in San Francisco, where over 241 individuals were exposed to the disease. The school, which charges $30,000 per year, has become a focal point for public health authorities due to the potential spread of the infection.
TB is caused by the bacteria Mycobacterium tuberculosis, which spreads easily through coughs and sneezes. Despite being referred to as a ‘Victorian era’ disease, it remains one of the deadliest globally, with more than 50 percent of patients dying without treatment. Children under five are particularly vulnerable.
Symptoms and Treatment Challenges
In the early stages, TB can cause a persistent cough and coughing up blood. As the disease progresses, it may lead to breathing difficulties, lung damage, and even death. It can also spread to other organs, such as the brain or spinal cord.
Treatment typically involves antibiotics, but some strains of TB are now resistant to these drugs, making treatment more complex. A vaccine exists to prevent TB, but it is not routinely offered in the US due to the country’s low incidence of the disease.
The new figures were revealed in a report from the California Department of Public Health, which was widely covered in local media. All patients had active infections, meaning the bacteria were causing symptoms. Some individuals were diagnosed with latent TB, where the disease is present but suppressed by the immune system.
Statistics and Public Health Response
In 2025, 279 people died from TB in California, accounting for 13 percent of all patients. Of these deaths, 24 percent did not receive treatment. The state’s annual incidence rate was 5.4 cases per 100,000 people, nearly double the national average of three cases per 100,000.
Forty-five of California’s 61 local health authorities reported at least one case of TB. Approximately 83 percent of cases were due to latent infections progressing to active ones, suggesting that better testing and treatment could have prevented many of these cases. About seven percent of cases involved individuals who had brought the disease into the state, while 10 percent resulted from recent transmission.
Since 2013, California has recorded between 2,000 and 2,100 TB infections annually, with a notable dip during the pandemic. This marked a 60 percent drop from the peak in 1992, when there were 5,300 cases. These numbers declined as part of a major public health initiative.
Ongoing Outbreak and Expert Opinions
Data on hospitalizations due to TB infections was not provided, nor was it clear how many cases California has recorded this year. Dr. Martin Willis, a former public health officer for Marin County, emphasized that TB thrives when individuals lose access to healthcare. He explained that those with latent TB may not be detected or treated, leading to active infections and further spread.
Provisional data shows that TB cases in the US dropped by one percent in 2024 compared to the previous year, but remained above 2011 levels. In the ongoing school outbreak, seven students have active TB, while 241 others have latent infections or carry the bacteria.
Dr. Monica Gandhi, an infectious disease expert at the University of California San Francisco, described the outbreak as significant. She noted that while latent TB does not cause symptoms, it is unusual to see such a high percentage of a school population diagnosed with the condition. “Kids in this country do not have latent TB like that,” she said. “Those kind of numbers, of 20 percent having latent TB, are in low-income countries.”
Global Impact and Future Outlook
TB infects a few thousand Americans each year and kills around 500, but the threat is far greater in developing countries. Globally, TB kills 1.2 million people annually. Public health officials continue to monitor the situation in California, emphasizing the need for improved access to care and early detection.
