A prolonged outbreak of tuberculosis (TB) in the Kansas City metropolitan area has raised significant concern among infectious disease experts and public health officials. Since its onset in January 2024, the outbreak has led to two confirmed fatalities and dozens of new diagnoses, drawing national attention. While initially referred to by state health officials as the largest TB outbreak in U.S. history, the Centers for Disease Control and Prevention (CDC) has clarified that larger outbreaks have occurred previously.

Understanding Tuberculosis

Tuberculosis is caused by the bacterium Mycobacterium tuberculosis, which primarily infects the lungs but can affect other organs. It is transmitted through aerosolized particles expelled when individuals with active TB cough, speak, or sing. Importantly, TB is not infectious during the latent phase, in which the individual harbors the bacteria without symptoms.

TB presents in two clinical forms:

• Active TB: Characterized by a persistent cough, hemoptysis (bloody sputum), fever, night sweats, weight loss, and lymphadenopathy.
• Latent TB Infection (LTBI): The bacteria remain dormant in the host, often localized in lung tissue. Individuals do not exhibit symptoms and are not contagious, although reactivation can occur, especially in immunocompromised individuals.

Globally, it is estimated that approximately 25% of the population is infected with M. tuberculosis, though only 5–10% of these individuals will progress to active disease during their lifetime.

Epidemiological Update: Kansas Outbreak

As of January 24, 2025, Kansas health authorities reported:

• 67 confirmed active TB cases, mostly within Wyandotte County
• 79 cases of latent TB
• Preliminary 2024 totals indicate 79 active and 213 latent TB cases across Wyandotte and Johnson Counties.

It remains unclear how many of these cases are directly tied to the current outbreak. Despite the elevated case count, state officials report signs of containment. According to Ashley Goss, Deputy Secretary at the Kansas Department of Health and Environment (KDHE), “we are trending in the right direction.”

Is This the Largest TB Outbreak in U.S. History?

Contrary to initial statements by state officials, the CDC has stated this is not the largest recorded TB outbreak in the United States. For comparison:

• Georgia (2015–2017): Over 170 active TB cases and 400 latent infections were linked to homeless shelters.
• Bone graft–related outbreak (2021): A contaminated tissue product resulted in 113 TB cases across multiple states.

Nevertheless, Kansas’ current outbreak is considered one of the most significant localized events in recent decades.

Treatment and Vaccination

TB is managed using a prolonged course of antibiotic therapy, typically involving a combination of drugs such as isoniazid, rifampin, ethambutol, and pyrazinamide over 6 to 9 months. Adherence to therapy is critical to prevent the development of drug-resistant TB.

The Bacille Calmette-Guérin (BCG) vaccine is available internationally but is not routinely recommended in the United States due to:

• Low endemic prevalence
• Limited efficacy in adults
• Interference with diagnostic tuberculin skin testing (TST)

A Global Health Perspective

While TB is relatively rare in the United States, it remains a leading cause of infectious disease mortality worldwide. According to 2023 World Health Organization (WHO) estimates:

• 1.25 million TB-related deaths occurred globally
• 8 million new infections were recorded—marking the highest annual case count since global surveillance began

In the United States, the 2023 TB case total exceeded 9,600, the highest number in over a decade, reflecting a troubling upward trend after years of decline.

Conclusion

Although the Kansas TB outbreak may not be the largest in U.S. history, it serves as a reminder of the ongoing threat posed by tuberculosis—even in high-income nations. Continued investment in surveillance, early diagnosis, community outreach, and treatment adherence will be key to preventing future resurgence.

Reference:
Associated Press. (2024, February). The tuberculosis outbreak in Kansas is alarming. It’s not the biggest in US history though, CDC says. Retrieved from https://apnews.com/article/tuberculosis-tb-outbreak-kansas-largest-b6b58f4f5461abb430745e3a8e7dc758