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Estimating the yield of tuberculosis from key populations to inform targeted interventions in South Africa: a scoping review
  1. Lucy Andere Chimoyi1,
  2. Christian Lienhardt2,
  3. Nishila Moodley1,
  4. Priya Shete2,
  5. Gavin J Churchyard1,3,
  6. Salome Charalambous1,4
  1. 1The Aurum Institute, Johannesburg, South Africa
  2. 2Global Tuberculosis Program, World Health Organisation, Geneva, Switzerland
  3. 3Department of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdo
  4. 4School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
  1. Correspondence to Lucy Andere Chimoyi; lchimoyi{at}


Introduction Tuberculosis (TB) case finding strategies are recommended to increase yield for TB in key populations. Several key populations are identified in the literature, but techniques for estimating yield and prioritising interventions are needed.

Methods We conducted a scoping review of existing evidence on TB burden to assess contribution of key populations to the TB epidemic in South Africa. Reports, articles and conference abstracts from January 2000 to December 2016 were reviewed to determine TB incidence, prevalence and size of key populations in South Africa. Meta-analysis summarised prevalence and incidence rates of TB in selected key populations assessed for heterogeneity. TB risk was calculated for each key population. Number needed to screen (NNS) to diagnose one case of TB disease was computed. Population attributable fraction estimated the potential impact of interventions on TB cases per population.

Results The search yielded 140 citations, of which 49 were included in the review and a final 32 were included in the meta-analysis. A high prevalence of TB disease was observed in HIV-infected patients with an estimated effect size (ES=0.25, 95% CI 0.20 to 0.30). Heterogeneity was high in this population (I2=94.8%, p value=0.000). The highest incidence rate of TB disease was observed in the HIV-infected population (ES=6.07, 95% CI 4.90 to 7.51). The risk of TB disease in South Africa was high in informal settlements (RR=5.8), HIV-infected (RR=5.4) and inmates (RR=5.0). Most cases of TB would be found in inmates (NNS=26) and household contacts of patients with TB (NNS=25). A larger impact would be observed if interventions are directed towards inmates (31%), people living with HIV (PLHIV (37%) and informal settlements (43%).

Conclusions Our findings illustrate the of value using available epidemiological evidence to inform targeted TB interventions. This review suggests that targeting interventions towards inmates, PLHIV and informal settlements would have a bigger impact on TB burden in South Africa.

  • epidemiology
  • tuberculosis
  • review

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  • Handling editor Seye Abimbola

  • Contributors SC, NM and PS contributed to the study conceptualisation. LAC and NM conducted data collection. LAC, NM, SC and PS contributed to data analysis/interpretation and creation of the first draft of the manuscript. LAC, SC, GJC and CL contributed to interpretation and revisions of the manuscript. All authors gave the final approval of the version to be published.

  • Funding The authors gratefully acknowledge the WHO for supporting this research through (award number 2017/703107-0).

  • Disclaimer The Global Tuberculosis Programme of the World Health Organisation, Geneva, supported this review. The content is the sole responsibility of the authors and neither represents the view of The Aurum Institute nor Global Tuberculosis Programme of the WHO, Geneva.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, conduct, reporting or dissemination plans of this research.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available upon request. All data relevant to the study are included in the article or uploaded as supplementary information. All data relevant to the study are included in the article or uploaded as supplementary information.Additional data are available on request.

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