Epidemiology of Tuberculosis and Its Elimination Program

1. Global Burden

• 10 million new TB cases annually
• Only 7 million of 10 million were reported to national health authorities (3 million "missed")
• 1.2 million deaths due to TB
• Case fatality rate: ~15%
• 86% of all cases occur in the WHO regions of Southeast Asia (44%), Africa (24%), and Western Pacific (18%)
• Most high-income countries have incidence below 10 per 100,000 - TB elimination is considered feasible there

2. TB Burden in India

• India accounts for 26% of global incident TB cases
• MDR/RR-TB in new cases: 2.8%; in previously treated cases: 14%
• TB treatment coverage (notified/estimated): 82%
• Case fatality ratio: 17%

Age Distribution in India

3. Risk Factors and Determinants

• Poverty, overcrowding, malnutrition, poor housing
• HIV co-infection
• Indoor air pollution, tobacco and alcohol abuse
• Diabetes mellitus
• Human migration (mixing infected and uninfected communities)
• Drug resistance (acquired due to poor TB programme performance, inadequate treatment)

4. Global TB Control Strategy Evolution

a. DOTS Strategy (mid-1990s to 2005)

1. Political commitment
2. Case detection by sputum smear microscopy
3. Standardized short-course chemotherapy with directly observed treatment
4. Regular, uninterrupted drug supply
5. Systematic monitoring and accountability

b. Stop TB Strategy (2006-2015)

• Pursuing quality DOTS - expansion and enhancement
• Addressing TB/HIV and MDR-TB
• Contributing to health system strengthening
• Engaging all care providers
• Empowering patients and communities
• Enabling and promoting research (diagnosis, treatment, vaccine)

c. End TB Strategy (2016-2030)

• Reduce TB deaths by 90% by 2030
• Reduce TB incidence by 80% by 2030
• Zero families burdened with catastrophic costs due to TB
• 2035 WHO targets: 95% reduction in deaths + 90% decline in incidence

1. Integrated, patient-centered care and prevention
2. Bold policies and supportive systems
3. Intensified research and innovation

• 40 million people treated for TB, including 3.5 million children and 1.5 million with DR-TB
• 30 million people provided TB preventive treatment, including 6 million PLHIV and 4 million children under 5 who are household contacts
• Funding of at least US$13 billion/year for universal TB care

5. India's National Tuberculosis Elimination Programme (NTEP)

Organizational Structure (5 levels):

Laboratory Network:

• National Reference Laboratories (NRLs): NTI Bengaluru, NIRT Chennai (also WHO Supra-National Reference Lab for South-East Asia Region), NITRD Delhi, JALMA Agra, RMRC Bhubaneswar, BMHRC Bhopal
• 27 Intermediate Reference Laboratories (IRLs): Culture and DST using phenotypic (solid LJ, liquid MGIT) and genotypic (LPA, CBNAAT) technology
• CBNAAT sites: To diagnose rifampicin resistance - Universal DST for all TB patients; 1,180 CBNAAT centres covering all districts

NTEP Endorsed Diagnostics:

1. Sputum smear microscopy (Ziehl-Neelsen stain; fluorescence with LED)
2. Culture - solid (Lowenstein-Jensen) or liquid (MGIT, Bactec)
3. Rapid molecular tests:
   • Line Probe Assay (LPA) - conventional PCR-based
   • NAAT (e.g., GeneXpert/CBNAAT) - real-time PCR

6. Drug-Resistant TB Management Under NTEP

• DR-TB Centres: 147 Nodal DR-TB Centres (NDRTBCs) established by 2017; one per ~10 million population
• District DR-TB Centres (DDRTBCs): For decentralized management of RR-TB and H mono/poly-resistance
• New drugs in use since 2018: Bedaquiline, Delamanid, shorter regimens
• Over 46,000 DR-TB patients initiated on shorter regimens; 7,973 on newer drug-containing regimens

7. Newer Initiatives Under NTEP

1. Daily fixed-dose combination (FDC) regimens for all forms of TB (including child-friendly FDCs in 6 weight bands)
2. Universal Drug Susceptibility Testing (Universal DST): ~55% of notified TB cases offered DST
3. Active Case Finding (Campaign Mode): Systematic TB screening in high-risk populations - tribal communities, slums, prisons, old-age homes, orphanages, transit camps
4. Bedaquiline and shorter DR-TB regimens expanded nationally
5. Ni-kshay Poshan Yojana: Nutritional support scheme (Rs. 500/month) to TB patients
6. Patient-wise drug boxes with blister packs (red for Cat I, blue for Cat II)

8. Principles of TB Control (Harrison's, 22nd Ed.)

• Early detection of all infectious cases
• Treatment under optimal case-management with social support until cure
• Regular screening of high-risk groups: immigrants from high-prevalence countries, migrants, prisoners, homeless individuals, substance abusers, PLHIV
• Contact investigation for all confirmed cases
• Interrupting transmission in institutional settings (hospitals, shelters, prisons): respiratory isolation, proper ventilation, UV irradiation, PPE, periodic screening of personnel

9. Recent Evidence (2024-2025)

• A 2025 systematic review (PMID: 40598516) identifies persistent diagnostic, treatment, and reporting gaps in India that contribute to millions of "missed" TB cases annually - a key barrier to elimination targets.
• A 2025 meta-analysis (PMID: 41143359) on delayed care in pulmonary TB from high-burden countries highlights that care delays remain a major challenge in meeting elimination timelines.

• Park's Textbook of Preventive and Social Medicine - Tuberculosis chapter and NTEP section
• Murray & Nadel's Textbook of Respiratory Medicine - Epidemiology of Tuberculosis chapter
• Harrison's Principles of Internal Medicine, 22nd Ed. (2025) - Principles of TB Control