Written By: Tavishi Dogra | Published : March 22, 2025 6:56 AM IST
Medically Verified By: Dr Subhashree Samantaray, Associate Consultant, Infectious Diseases, Manipal Hospitals, Bhubaneswar
Tuberculosis (TB) remains a significant public health challenge in India, with around 27% of global TB burden. It is a contagious disease caused by the bacteria Mycobacterium tuberculosis, which does not respond to conventional antibiotics because of unique structure of its cell wall. Patients infected with TB can develop symptoms like persistent cough, haemoptysis, fever, night sweats, weight loss, sometimes chest pain, shortness of breath, fatigue or anorexia and can shed the bacteria in their cough and sneezes.
Such symptomatic cases are known as active TB cases, which can be detected through clinical examination, chest X-ray or sputum examination. A person with active pulmonary TB can release infectious aerosols containing bacteria, that can stay airborne for hours in poorly ventilated spaces, increasing the risk of inhalation by others. The active TB cases are managed with weight-band based anti-tubercular treatment regimens consisting of 2 months of HRZE followed by 4 months of HRE, which may be extended or individualized based on patient's clinical or radiological cure.
When a person with good immunity gets exposed to active TB cases, he may develop latent TB infection (LTBI), which is nothing but, a state of persistent immune response to Mycobacterium tuberculosis antigens. Such individuals harbour the bacteria in their body, but do not develop symptoms of active TB and hence are not infective to others. From the pool of latent TB cases, 5-10% mostly develop active TB disease over the course of their lives, usually within the first 5 years depending on the patient's immunological status. Various tests like Interferon Gamma Release Assay (IGRA) and Tuberculin skin test are recommended for screening the patients for LTBI. However, routine screening of LTBI is not recommended as they give positive results in both TB infected and exposed population.
These screening tests are used only in certain risk groups like, adults and children living with HIV, household contacts of active TB cases with immunosuppressed status such as, those on chemotherapy or immunomodulators, patients receiving dialysis, or those preparing for an organ or haematological transplant and patients with chronic lung conditions. If found positive, these groups are started on TB Preventive Treatment (TPT), because of their high risk of progression to active TB.
WHO, CDC and Government of India have recommended TPT, in form of Isoniazid monotherapy for 6 months Or Rifampicin or rifabutin plus isoniazid daily for 3 months for the LTBI cases. However, it is always essential to rule out active TB before initiating TPT, else it can lead to sub-optimal clinical response in active TB, later on leading to disseminated disease involving multiple organs and even drug resistance. Management of active TB and LTBI is available free of charge through national programmes.
