What should you know about BCG vaccine and latent TB?

Latent tuberculosis infection means TB bacteria are present in the body without the person having active TB illness. People with latent infection generally do not have the symptoms associated with active disease and cannot spread TB through ordinary contact, but the infection can become active in some circumstances. BCG vaccination changes how some TB tests are interpreted, so a clinician chooses screening methods with your vaccination history in mind.

A positive screening result is not the same as active tuberculosis. Assessment may include questions about exposure, symptoms, examination, and further tests. The purpose is to separate latent infection from active disease and decide whether preventive treatment is appropriate.

Tell the healthcare team when and where you received BCG, whether you have lived with or spent time near someone with TB, and whether you have immune conditions or medicines that affect immunity. Attend recommended screening appointments and keep copies of results. If latent infection is diagnosed, discuss the proposed antibiotic treatment, its duration, interactions, and symptoms that should be reported. Do not start leftover antibiotics yourself.

Arrange prompt medical assessment for a cough that does not settle, coughing blood, unexplained fever, night sweats, weight loss, chest pain, or worsening breathlessness, especially after TB exposure. Seek emergency care for severe breathing difficulty, confusion, or coughing large amounts of blood. These symptoms can have other causes, but active TB needs timely evaluation.

Ask which screening test is suitable after BCG, what a result means in your case, whether a chest assessment is needed, and how preventive antibiotic treatment would be monitored.