TBC040: Screening, Treatment, and Transmission Control

1. Impact of BCG Vaccination Policies on TB Epidemiology

• Stopping universal BCG vaccination does not universally increase childhood TB cases.
• Only Slovakia saw a significant rise in childhood TB rates; other countries (Norway, France, UK) remained stable or declined. See also: https://idebeasiswa.com
• Migration patterns influenced TB rates, especially in France and Norway.
• Pulmonary TB and TB lymphadenitis were the most common forms; severe TB cases stayed below 4%.
• Discontinuation could raise TB burden in high vaccine efficacy regions, but selective vaccination is a viable alternative.
• Strong surveillance and targeted vaccination strategies are necessary.

2. Challenges in Pediatric TB Diagnosis and Care

• Diagnosing pediatric TB is difficult due to sample collection challenges.
• Alternative methods (stool, nasopharyngeal aspirates) offer similar sensitivity to induced sputum.
• Many children with TB symptoms remain undiagnosed due to limited diagnostic accessibility.
• Decentralizing TB services to district hospitals (DHs) is cost-effective in high-prevalence areas.
• Extending services to primary health centers (PHCs) is less feasible due to cost and efficiency concerns.
• DHs detect more TB cases due to better diagnostic tools and referral practices.

3. Innovations in TB Diagnosis and Treatment

• A new diagnostic tool is expected to accelerate pulmonary TB burden reduction.
• Most beneficial in areas with good TB care access but limited diagnostic sensitivity.
• Less impact in reference labs with high diagnostic accuracy.
• Could improve patient trust, reduce diagnosis delays, and minimize repeated healthcare visits.

4. TB Screening, Surveillance, and Transmission Control

• Screening and treating latent and asymptomatic TB infections significantly reduce transmission rates.
• The most effective approach combines vaccination, screening, and treatment.
• Study in Eastern Cape, South Africa, identified key TB surveillance challenges: Transport issues for community health workers (CHWs). Community distrust and resource disparities between rural and urban areas. Need for tailored TB surveillance interventions.

5. TB in High-Risk Populations: Loss to Follow-Up and Occupational Risk

• Study in Kenya found a 42.4% pre-treatment loss to follow-up (PTLFU) rate in pulmonary TB patients.
• Major risk factors: limited contact details and older age (≥55 years).
• Sex, HIV status, and prior TB treatment did not significantly affect PTLFU.
• Healthcare workers (HCWs) in Taiwan have a higher TB incidence than the general population.
• HCWs have better TB outcomes due to early diagnosis, treatment, and the "healthy worker effect."

References:

1. Kobayashi, S., Yoshiyama, T., Uchimura, K., Hamaguchi, Y. and Kato, S., 2021. Epidemiology of childhood tuberculosis after ceasing universal Bacillus Calmette–Guérin vaccination. Scientific Reports, 11(1), p.15902.
2. Fu, H., Lin, H.H., Hallett, T.B. and Arinaminpathy, N., 2018. Modelling the effect of discontinuing universal Bacillus Calmette-Guérin vaccination in an intermediate tuberculosis burden setting. Vaccine, 36(39), pp.5902-5909.
3. d'Elbée, M., Harker, M., Mafirakureva, N., Nanfuka, M., Nguyet, M.H.T.N., Taguebue, J.V., Moh, R., Khosa, C., Mustapha, A., Mwanga-Amumpere, J. and Borand, L., 2024. Cost-effectiveness and budget impact of decentralising childhood tuberculosis diagnosis in six high tuberculosis incidence countries: a mathematical modelling study. EClinicalMedicine, 70, p.102528.
4. Lin, H.H., Dowdy, D., Dye, C., Murray, M. and Cohen, T., 2012. The impact of new tuberculosis diagnostics on transmission: why context matters. Bulletin of the World Health Organization, 90, pp.739-747.
5. Mulaku, M.N., Ochodo, E., Young, T. and Steingart, K.R., 2024. Pre-treatment loss to follow-up in adults with pulmonary TB in Kenya. Public Health Action, 14(1), pp.34-39.
6. Kirimi, E.M., Muthuri, G.G., Ngari, C.G. and Karanja, S., 2024. A Model for the Propagation and Control of Pulmonary Tuberculosis Disease in Kenya. Discrete Dynamics in Nature and Society, 2024(1), p.5883142.
7. Ajudua, F.I. and Mash, R.J., 2024. Implementing active surveillance for TB: A descriptive survey of healthcare workers in the Eastern Cape, South Africa. African Journal of Primary Health Care & Family Medicine, 16(1), p.4217. See also: https://tbreadingnotes.blogspot.com/2024/07/tuberculosis-in-healthcare-workers.html
8. Pan S-C, Chen Y-C, Wang J-Y, Sheng W-H, Lin H-H, Fang C-T, et al. (2015) Tuberculosis in Healthcare Workers: A Matched Cohort Study in Taiwan. PLoS ONE 10(12): e0145047.