2017 State and City TB Report
Treatment for Latent TB Infection
When a person with infectious TB coughs (or sneezes or sings or talks), droplet nuclei containing M. tuberculosis are expelled into the air. If another person inhales air containing these droplet nuclei, he or she may become infected. However, not everyone infected with TB bacteria develops symptoms of TB. As a result, two TB-related conditions exist: LTBI and TB disease. Persons with LTBI do not feel sick and do not have any symptoms. They are infected with M. tuberculosis, but do not have TB disease. The only sign of LTBI is a positive reaction to a TB skin test or TB blood test. Persons with LTBI are not infectious and cannot spread TB to others. However, at some point in their lives, 5-10% of all people with normal immune systems who have LTBI will become sick with TB disease. As previously described, the chances of progression from LTBI to TB disease are higher for persons with weakened immune systems, such as those infected with HIV. LTBI can be treated to prevent progression to TB disease. Thus, it is important, in terms of accelerating the decline in TB incidence, to measure how many people with LTBI begin and complete treatment.
TB programs work to identify persons who are at high risk for LTBI or at high risk for developing TB disease once infected so that they can offer testing and treatment for LTBI. High-risk persons include known close contacts of someone with infectious TB disease, persons from regions of the world with high TB incidence, and those who work or reside in facilities or institutions with people who are also at high risk for TB. Risk factors for developing TB disease once infected include HIV infection, injection drug use, evidence of prior healed TB disease, diabetes, or low body weight. Infants and children under the age of five years are also at higher risk of getting sick with TB disease once infected.
In 2016, the most recent year for which data are available, 11 states met or exceeded the 2020 national target of initiating treatment for 91.0% of people diagnosed with LTBI found during contact investigations; 23 states and 6 cities were short of the 2020 target, but exceeded the national average of 71.5% (Figure 11image icon).
In 2016, 23 states and 4 cities met or exceeded the 2020 national target of treatment completion for 81.0% of people diagnosed with LTBI through contact investigation who started treatment; 4 states and 2 cities were short of the 2020 target, but met or exceeded the national average of 77.5% (Figure 12image icon).