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.
U.S. TB incidence increased during 2022, compared with that during 2020 and 2021, but remained lower than incidence during the prepandemic years; after a substantial 20.2% decline in 2020 and partial rebound (9.8% increase) in 2021, incidence appears to be returning to prepandemic levels among U.S.-born and non–U.S.-born populations.
During 2022, 8,300 TB cases were reported in the United States, compared with 7,874 during 2021. TB incidence during 2022 increased slightly to 2.5 per 100,000 persons, compared with 2.4 during 2021. Consistent with previous years (1), in 2022, California reported the highest number of TB cases (1,843) and Alaska reported the highest TB incidence (13.1)
COVID-19–associated mortality was high among persons aged ≥65 years, which might account, in part, for the lower TB incidence observed among that population. Even though the decrease in TB incidence was small, reduction of the population aged ≥65 years at risk for TB might have similar effects on TB incidence in future years.
The increase in TB incidence among children aged ≤4 years might represent both recent transmission in the United States and infection in countries with higher TB incidence. An analysis of TB incidence among indigenous persons during 2009–2019 found a higher prevalence of underlying chronic medical conditions, and TB incidence was at least 10 times higher among AI/AN and NH/OPI persons than among White persons. These factors likely contributed to the higher TB incidence in these populations in this report. Among non–U.S.-born persons with TB, the higher proportion reported <1 year after arrival in the United States might reflect greater migration from higher TB incidence areas than what existed at the beginning of the pandemic.
Although preventing TB transmission in the United States remains a priority, >80% of U.S. TB cases are attributed to reactivation of LTBI. To achieve TB elimination in the United States, the U.S. Preventive Services Task Force recommends testing and treatment among populations at higher risk for LTBI, including non–U.S.-born persons and persons in congregate living settings.
To treat LTBI, CDC recommends short-course (3- or 4-month), rifamycin-based regimens. Shorter regimens are also available to treat TB: in 2022, CDC recommended a 4-month treatment regimen for drug-susceptible pulmonary TB as an alternative to the standard 6-month regimen (6). Shorter treatment durations improve treatment adherence and completion.
On July 7, 2023, a state health department notified CDC that an otherwise healthy adult experienced symptoms of meningitis 5 weeks after spinal fusion surgery that incorporated a bone allograft product containing live cells; Mycobacterium tuberculosis was identified in the cerebrospinal fluid.
On July 11, a different state health department notified CDC of a patient with a persistent surgical site infection after a laminectomy that appeared to have used a similar product; drainage from the surgical site tested positive for acid-fast bacilli, and a nucleic acid amplification test confirmed the presence of M. tuberculosis. When reporting these cases to their respective public health authorities, the clinicians caring for these two patients independently noted similarities to the 2021 outbreak and asked that CDC investigate.
After receiving the first case report, CDC notified the Food and Drug Administration (FDA) and requested that the tissue establishment* quarantine (i.e., store and prohibit use of) any remaining tissue from this donor (i.e., same product lot). On July 11, the tissue establishment quarantined the 53 units that had not yet been distributed and provided a list of all health care facilities that had purchased tissue units from that lot. Eight hospitals and five dental offices in seven states (California, Louisiana, Michigan, New York, Oregon, Texas, and Virginia) received a total of 50 bone allograft units from this product lot during February 27–June 20, 2023.
This second nationwide TB outbreak in 2023 was detected when clinicians in two states recognized similarities to the 2021 outbreak and reported their concerns to their respective health departments, thereby initiating a rapid public health response that prevented as many as 53 additional surgical procedures with the implicated bone allograft material. Before the 2021 TB outbreak, which involved 113 recipients in 18 states, bone allograft–related M. tuberculosis transmission had last been reported in the United Kingdom in 1953.