Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis, most commonly affecting the lungs. While often viewed as a historical disease in developed nations, it has not been eradicated from the United States. The country has achieved a low incidence rate, a significant public health success, but cases persist, meaning the infection still circulates.
Current TB Prevalence in the US
In 2023, the US reported 9,633 cases of active TB disease, corresponding to a rate of 2.9 cases per 100,000 persons. This represented the third consecutive year of increase, surpassing pre-pandemic levels, with provisional data for 2024 showing a further rise to 10,347 cases. Active TB disease is a nationally notifiable condition, meaning every case must be reported to health departments, which allows for precise tracking of transmission.
Latent TB Infection (LTBI) is far more common than active disease. An estimated 13 million people in the US are infected with the bacteria but are asymptomatic and cannot transmit the disease. This latent state is concerning because the progression from untreated LTBI to active TB disease accounts for approximately 80% of all new TB cases. The national rate, however low, masks significant disparities in the burden of the disease.
The majority of active TB cases occur among non-U.S.–born persons, who accounted for over 75% of cases in 2023, with an incidence rate 18.5 times higher than that of U.S.-born persons. This concentration reflects the high TB prevalence in many countries of origin. Geographically, a few states report a disproportionate number of cases, with California, Texas, New York, and Florida collectively reporting over half of all cases nationally in 2023.
Factors Preventing TB Elimination
The dormant reservoir of Latent TB Infection within the population is a major barrier to elimination. These millions of individuals harbor the Mycobacterium tuberculosis bacteria, which can reactivate years or even decades later, particularly if the host’s immune system weakens. Since this population is largely asymptomatic, finding and treating them requires proactive, targeted screening efforts. Without addressing this reservoir, new cases will continue to emerge from within the US population.
The persistent global burden of TB affects elimination efforts through international travel and immigration. TB is endemic in many parts of the world, and most cases among non-U.S.-born persons were acquired before they arrived. The continuous introduction of the bacteria prevents domestic transmission from reaching zero, making the goal of elimination—defined as less than one case per million people annually—difficult to achieve.
Drug-resistant strains of the bacteria complicate control efforts. Drug-resistant TB develops when treatment is incomplete or improperly administered, allowing the most resilient bacteria to survive and multiply. Multi-Drug Resistant TB (MDR-TB), which is resistant to the two most effective first-line drugs, isoniazid and rifampin, accounted for 100 cases in 2023. The emergence of Extensively Drug Resistant TB (XDR-TB) is a serious threat because it requires longer, more toxic, and less effective treatment regimens.
Public Health Strategies for Control and Treatment
Public health efforts in the US employ a dual approach focused on treating active TB disease and testing and treating Latent TB Infection to prevent progression. A primary strategy is the rapid identification and treatment of individuals with active disease to stop transmission. This is coupled with intensive contact investigations, where public health officials trace and test anyone exposed to an infectious patient.
The standard treatment for active TB disease involves a multi-drug regimen that typically lasts six to twelve months for drug-susceptible cases. To ensure patients complete the course of medication, public health programs often utilize Directly Observed Therapy (DOT). In DOT, a healthcare worker meets with the patient daily to watch them ingest their doses. This practice helps prevent drug resistance and ensures a cure.
Health departments focus on testing high-risk groups for LTBI, such as non-U.S.-born individuals from high-prevalence countries and people with compromised immune systems. The treatment for LTBI is designed to kill the dormant bacteria and prevent the development of active disease. Modern short-course regimens are now being scaled up to improve patient adherence.