latent tuberculosis

Latent tuberculosis, also known as latent TB infection, occurs when a person is infected with the Mycobacterium tuberculosis bacterium but does not have active TB disease. In this state, the bacteria are contained by the immune system and do not cause symptoms, nor is the person contagious.1

While the individual is not sick, the bacteria remain alive in the body. In some cases, the latent infection can reactivate later, sometimes after many years, leading to active TB disease. This reactivation can happen if the immune system weakens, for example, due to conditions like HIV/AIDS, or other health issues.12

Diagnosis of latent TB typically involves skin tests or blood tests, such as the tuberculin test or interferon-gamma release assays. These tests indicate infection but cannot differentiate between latent and active TB. Treatment for latent TB aims to prevent the disease from developing and usually involves a single medication.132