Tuberculosis (TB), a bacterial infection primarily affecting the lungs, has not been eradicated in the United States. While active cases have declined substantially since the mid-20th century, the disease remains a persistent public health challenge. The goal of eliminating TB from the US, defined as fewer than one case per million people annually, is still unmet. Public health programs must maintain constant vigilance to prevent widespread transmission.
Current Status of Tuberculosis in the US
The US maintains one of the lowest TB incidence rates globally, yet the disease continues to be reported annually. In 2023, the US reported 9,615 cases of active TB disease, an incidence rate of 2.9 cases per 100,000 persons. This count marked the third consecutive year of increase since 2020 and was the highest number reported since 2013, highlighting the difficulty in achieving sustained reduction.
The burden of TB is concentrated in specific groups. In 2023, about 76% of reported cases occurred in persons born outside of the United States, where the incidence rate was 18.5 times higher than among US-born persons. The disease also disproportionately affects racial and ethnic minorities, accounting for over 90% of cases reported in 2023.
Age also plays a role, with the highest incidence rates seen in persons aged 65 years or older. Underlying medical conditions, such as HIV infection and diabetes, significantly increase the risk of progression to active disease. These demographic and medical risk factors inform targeted testing and treatment strategies.
Factors Preventing Eradication
The primary reason TB has not been eliminated is the massive reservoir of Latent TB Infection (LTBI) within the population. LTBI occurs when a person is infected with Mycobacterium tuberculosis but does not have active disease symptoms because the immune system has contained the bacteria. The CDC estimates that up to 13 million people in the US have LTBI, creating a large pool of potential future active cases.
Untreated LTBI can reactivate years or decades later, especially if the immune system weakens, leading to contagious active TB disease. Progression from latent infection accounts for a significant majority of all new TB cases in the US. This means that even if all current active cases were successfully treated, the disease would continue to resurface from this hidden reservoir.
Another challenge is the emergence of drug-resistant strains, which complicates treatment and containment. Multidrug-Resistant TB (MDR-TB) is resistant to the two most effective first-line drugs, isoniazid and rifampin. Extensively Drug-Resistant TB (XDR-TB) is resistant to first-line drugs plus certain second-line treatments. While drug-resistant cases are rare (100 MDR-TB cases reported in 2023), these strains require longer and more complex treatment regimens.
The global context of TB also contributes to its persistence, as international travel and immigration facilitate the introduction of new cases. Individuals arriving from high-prevalence areas often carry latent or active infection. This continuous introduction maintains transmission chains within the US.
Public Health Strategies for TB Control
Public health authorities employ a multi-faceted approach centered on surveillance, case management, and prevention. A national surveillance system mandates that all suspected and confirmed cases of active TB disease are reported to state and local health departments. This mandatory reporting allows for the timely tracking of every case, including demographic and drug-resistance information, essential for monitoring trends and directing resources.
Once an active case is identified, the response focuses on ensuring the patient completes the lengthy treatment regimen. Treatment for drug-susceptible active TB involves a combination of antibiotics taken for six to nine months. To ensure compliance and prevent drug resistance, many patients receive Directly Observed Therapy (DOT), where a healthcare worker watches the patient swallow every dose of medication.
A primary public health tool is contact tracing, where staff identify and screen individuals who have had close contact with an infectious TB patient. Contacts are tested using diagnostic methods like the tuberculin skin test (TST) or interferon-gamma release assays (IGRAs). If a contact has LTBI, they are offered treatment, often a shorter course lasting three to four months, to prevent progression to active disease and break the transmission cycle.