California is outpacing much of the rest of the nation in cases of tuberculosis, according to the federal Centers for Disease Control and Prevention.

In California, 2,150 people were diagnosed with TB in 2025, an increase of 41 cases from the previous year, according to the CDC

California had 5.5 tuberculosis cases per 100,000 people on average, according to the CDC’s latest provisional tuberculosis data report, released in March. That’s the highest rate the state has reported in 12 years, the CDC said.

As a whole, the United States saw an average of three TB cases per every 100,000 people in 2025, according to federal data. Here’s what to know about the highly contagious lung disease: What is tuberculosis? Tuberculosis is a disease caused by bacteria that usually attack the lungs. Although rare, the disease can be deadly if left untreated. TB was once considered “an ancient scourge,” according to Science Direct, leading to epidemics in Europe and North America during the 18th and 19th centuries. An outbreak in January among high school students in San Francisco points to the persistence of the disease, which has both active and latent stages, according to previous reporting by The Mercury News.

How common is tuberculosis? Most people in the United States are at low risk for tuberculosis, the CDC said, and TB rates in the nation are lower than in developing countries. In California, 2,150 people were diagnosed with TB in 2025, an increase of 41 cases from the previous year, according to the CDC.

Story Date: May 8, 2026