Can we ignore latent tuberculosis infection if there are no symptoms?

There are a large number of tuberculosis patients and people with latent tuberculosis infection in my country. An important part of tuberculosis prevention and control is how to effectively identify tuberculosis patients and people with latent tuberculosis infection.

It is estimated that there are about 200 million people in China with latent tuberculosis infection , of which about 5% to 10% will develop active pulmonary tuberculosis in their lifetime . The incidence rate is even higher among people at high risk of tuberculosis, especially among children under 5 years old who have close family contacts with confirmed tuberculosis patients. The 2-year tuberculosis incidence rate can be as high as 19%.

So how should we deal with latent tuberculosis infection? Let's read on.

What is latent tuberculosis infection?

Latent tuberculosis infection (LTBI) refers to the presence of Mycobacterium tuberculosis in the body without clinical symptoms and signs of tuberculosis and without evidence of active tuberculosis in clinical bacteriology and imaging.

Simply put, the human body is infected with tuberculosis bacteria and has an immune response but no clinical manifestations, no cough, sputum, fever, no afternoon low fever, night sweats and other tuberculosis symptoms, the patient does not feel unwell, and chest X-rays and CT scans show no signs of tuberculosis .

How to identify latent tuberculosis infection?

Commonly used detection methods for tuberculosis infection include skin testing and interferon-gamma release assay (IGRA) .

Skin tests are low-cost and easy to perform, and are widely used immunological methods for screening tuberculosis infection in clinical practice, including tuberculin skin test (TST) and creation tuberculin skin test (C-TST). The cost of interferon-γ release test is relatively high and the operation is relatively complicated, but the test results are not affected by factors such as BCG vaccination and multiple non-tuberculous mycobacterial infections.

Doctors use the above tests to determine whether the patient is infected with Mycobacterium tuberculosis, and exclude active tuberculosis through interviews, physical examinations, chest imaging examinations, etc., and then consider diagnosing LIBI.

How to prevent latent tuberculosis infection from developing into

Active tuberculosis?

Studies have shown that preventive treatment for key populations with latent tuberculosis infection can achieve a 60%-90% protective effect, thereby reducing the incidence of tuberculosis. Preventive treatment includes chemical prevention and immunoprevention , which should be selected based on specific circumstances.

Chemical prevention : LTBI preventive treatment options include isoniazid alone, isoniazid combined with rifampicin, isoniazid combined with rifapentine, and rifampicin alone. Appropriate options can be selected based on the characteristics of different populations.

Immunoprevention : The use of injectable bovine Mycobacterium preparations can not only mediate and enhance protective immune responses, but also inhibit allergic reactions and inhibit or reduce pathological damage, thereby exerting a bidirectional immunoregulatory effect.