The physical space of the MSK Library is permanently closed to visitors as of Friday, May 17, 2024. Please visit this guide for more information.
The physical space of the MSK Library is permanently closed to visitors as of Friday, May 17, 2024. Please visit this guide for more information.
Tuberculosis (commonly referred to as "TB") is a highly contagious bacterial infection caused by a bacterium called Mycobacterium tuberculosis. While it most commonly attacks the lungs but it can also cause infections in any part of the body. It can also cause latent infection without making a person actually sick.
TB bacteria can live in the body without making you sick. This is called latent TB infection. In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing. People with latent TB infection:
Many people who have latent TB infection never develop TB disease. In these people, the TB bacteria remain inactive for a lifetime without causing disease. But in other people, especially people who have a weak immune system, the bacteria become active, multiply, and cause TB disease.
TB bacteria become active if the immune system can’t stop them from growing. When TB bacteria are active (multiplying in your body), this is called TB disease. People with TB disease are sick. They may also be able to spread the bacteria to people they spend time with every day.
Many people who have latent TB infection never develop TB disease. Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB bacteria. Other people may get sick years later when their immune system becomes weak for another reason.
Symptoms of TB disease in other parts of the body depend on the area affected
Tuberculosis disease is treated with antibiotics. Treatment is recommended for both TB infection and disease.
The most common antibiotics used are:
To be effective, these medications need to be taken daily for 4–6 months. It is dangerous to stop the medications early or without medical advice. This can allow TB that is still alive to become resistant to the drugs.
Tuberculosis that doesn’t respond to standard drugs is called drug-resistant TB and requires more toxic treatment with different medicines.
In certain countries, the Bacille Calmette-Guérin (BCG) vaccine is given to babies or small children to prevent TB. The vaccine prevents TB outside of the lungs but not in the lungs.
Drug resistance emerges when TB medicines are used inappropriately, through incorrect prescription by health care providers, poor quality drugs, or patients stopping treatment prematurely.
Multidrug-resistant tuberculosis (MDR-TB) is a form of TB caused by bacteria that do not respond to isoniazid and rifampicin, the 2 most effective first-line TB drugs. MDR-TB is treatable and curable by using second-line drugs. However, second-line treatment options require extensive medicines that are expensive and toxic.
In some cases, more extensive drug resistance can develop. TB caused by bacteria that do not respond to the most effective second-line TB drugs can leave patients with very limited treatment options.
MDR-TB remains a public health crisis and a health security threat. Only about 1 in 3 people with drug resistant TB accessed treatment in 2021.
In 2022, new WHO guidelines prioritize a 6-month regimen – the BPaLM/BPaL – as a treatment of choice for eligible patients. The shorter duration, lower pill burden and high efficacy of this novel regimen can help ease the burden on health systems and save precious resources to further expand the diagnostic and treatment coverage for all individuals in need. In the past, MDR-TB treatment used to last for at least 9 months and up to 20 months. WHO recommends expanded access to all-oral regimens.
Prior to the COVID-19 pandemic, TB case counts and rates had been steadily declining in the United States since 1992. During 2020, the first year of the COVID-19 pandemic, TB cases decreased by 19.4% and the incidence rate decreased by 20.2%. TB case counts and incidence rates subsequently increased in 2021 and 2022. In 2023, the TB case count and incidence rate rose to above pre-pandemic levels.
In 2023, the United States reported 9,633 cases of TB disease. This represents an increase in case count by:
Consistent with previous years, birth outside of the United States remained a key risk factor for TB disease in 2023. The TB incidence rate was 18 times higher among non-U.S.–born persons compared with U.S.-born persons. Despite prevention efforts, TB affects some groups of people more than others. In the United States, TB adversely affects groups that have historically experienced greater obstacles to health care.
Public health workers are currently battling one of the largest tuberculosis outbreaks in US history in the Kansas City metro area, including the counties of Wyandotte and Johnson. The outbreak was first reported in January 2024, and has since lead to dozens of cases and two deaths.
Data as of: February 14, 2025
The number of outbreak-associated active TB cases reported since January 2024:
Active TB cases associated with this outbreak include all individuals diagnosed with confirmed active TB infection since the outbreak was first identified in January 2024.
Once individuals complete the full course of treatment (~6 months), while their cases are still classified as "active TB" they are considered cured or successfully treated and no longer contagious.
The number of outbreak-associated latent TB cases reported since January 2024:
Following standard practice in infectious disease investigations, local health departments are working with each patient to identify possible close contacts and conduct TB testing at no cost.
Patients who test positive will be further screened to determine if they have active TB disease or latent TB infection, which will help determine the best treatment. Treatment will be provided through the patient's local health department, and it will be provided for free if the person is uninsured or the treatment isn’t covered by health insurance.
Health department staff will remain in touch with patients throughout treatment to help them stay on course and address any questions or concerns they may have.
As of January 31, 2025, "KDHE is currently managing 384 individuals associated with this outbreak who are at various stages of TB testing, diagnosis, and treatment." The CDC has dispatched four experts to Kansas to help state and local public health workers respond to the outbreak.
"The current Kansas City, Kan. Metro tuberculosis (TB) outbreak is the largest documented outbreak in U.S. history, presently (since the 1950’s, when the Centers for Disease Control and Prevention (CDC) started monitoring and reporting TB cases)," KDHE communications director Jill Bronaugh told CIDRAP News in an email. "This outbreak is still ongoing, which means that there could be more cases."