Transmission and Management of Latent and Active Tuberculosis

Understanding Latent TB vs. Active TB

Patients with latent tuberculosis infection (LTBI) are asymptomatic, have negative chest radiographs, and cannot transmit the infection to others, according to the Centers for Disease Control and Prevention 3, 4
Only patients with active pulmonary or laryngeal TB can transmit the infection through aerosolized droplet nuclei produced by coughing, sneezing, speaking, or singing, as stated by the Infectious Diseases Society of America 5, 6
The most infectious individuals are those who have not been treated for TB and have one or more of the following: pulmonary or laryngeal TB with cough, positive AFB sputum smear, or cavitation on chest radiograph, as reported by the Centers for Disease Control and Prevention 1

Transmission of TB requires the following conditions: active disease in the lungs or larynx, presence of cough or undergoing cough-inducing procedures, positive acid-fast bacilli (AFB) sputum smears, and inadequate or no treatment, according to the Centers for Disease Control and Prevention 1, 5, 6
Extrapulmonary TB is generally not infectious unless there is concomitant pulmonary disease, disease in the respiratory tract/oral cavity, or an open abscess with high concentration of organisms, as stated by the Centers for Disease Control and Prevention 1

Healthcare workers with latent TB infection should not be restricted from their usual work activities and do not require isolation, as recommended by the Centers for Disease Control and Prevention 2, 4, 7
Only patients with active pulmonary or laryngeal TB require respiratory isolation until they are determined to be non-infectious, according to the Infectious Diseases Society of America 5, 6

Certain individuals with LTBI have higher risk of progression to active TB, including HIV-infected persons, recent converters, children under 5 years of age, persons with fibrotic lesions on chest radiographs, and persons with certain medical conditions, as reported by the Centers for Disease Control and Prevention 8

Contact investigations are necessary for active TB cases but not for latent TB cases, as LTBI is not transmissible, according to the Centers for Disease Control and Prevention 9
Persons with LTBI should be evaluated for preventive treatment to reduce their risk of developing active TB, which would then pose a transmission risk to others, as recommended by the Centers for Disease Control and Prevention 8
The Centers for Disease Control and Prevention recommends that healthcare facilities have clear protocols for distinguishing between latent TB and active TB to guide appropriate isolation and infection control measures, as stated by the Centers for Disease Control and Prevention 1, 2