Abstract
Background We aimed to evaluate the effectiveness of contact investigation in comparison with passive case detection alone, and estimate the yield of co-prevalent and incident tuberculosis (TB) and latent TB infection (LTBI) among contacts of patients with TB.
Methods A systematic search was undertaken of studies published between 1 January 2011 and 1 October 2019 in the English language. The proportion of contacts diagnosed with co-prevalent TB, incident TB and/or LTBI was estimated. Evaluation of the effectiveness of contact investigation included randomised trials, while the yield of contact investigation (co-prevalent/incident TB and LTBI) was assessed in nonrandomised studies.
Results Data were extracted from 244 studies, of which 187 studies measured the proportion of contacts diagnosed with TB disease and 135 studies measured LTBI prevalence. Individual randomised trials demonstrated that contact investigation increased TB case notification (relative risk 2.5, 95% CI 2.0–3.2) and TB case detection (OR 1.34, 95% CI 0.43–4.24) and decreased mortality (relative risk 0.6, 95% CI 0.4–0.8) and population TB prevalence (risk ratio 0.82, 95% CI 0.64–1.04). The overall pooled prevalence of TB was 3.6% (95% CI 3.3–4.0%; I2=98.9%, 181 studies). The pooled prevalence of microbiologically confirmed TB was 3.2% (95% CI 2.6–3.7%; I2=99.5%, 106 studies). The pooled incidence of TB was highest in the first year after exposure to index patients (2.0%, 95% CI 1.1–3.3%; I2=96.2%, 14 studies) and substantially lower 5 years after exposure to index patients (0.5%, 95% CI 0.3–0.9%; one study). The pooled prevalence of LTBI among contacts was 42.4% (95% CI 38.5–46.4%; I2=99.8%, 135 studies).
Conclusions This systematic review and meta-analysis found that contact investigation was effective in high-burden settings. The higher pooled prevalence estimates of microbiologically confirmed TB compared with previous reviews suggests newer rapid molecular diagnostics contribute to increased case detection.
Abstract
Contact investigation is associated with increased case detection, reduced mortality and decreased community prevalence of TB, and resulted in a high yield of co-prevalent, incident and latent TB infection among contacts https://bit.ly/3h9jW2H
Footnotes
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Author contributions: K. Velen had full access to all the data collected in this study and takes full responsibility for the integrity of the data and accuracy of the analysis. R.V. Shingde, J. Ho and G.J. Fox are all equal contributors to the manuscript. Concept and design: K. Velen and G.J. Fox. Acquisition, analysis or interpretation of data: all authors. Drafting of the manuscript: K. Velen and G.J. Fox. Critical revision of the manuscript: all authors. Statistical analysis: K. Velen. Obtained funding: G.J. Fox. Study supervision: K. Velen and G.J. Fox.
Conflict of interest: K. Velen has nothing to disclose.
Conflict of interest: R.V. Shingde has nothing to disclose.
Conflict of interest: J. Ho has nothing to disclose.
Conflict of interest: G.J. Fox has nothing to disclose.
Support statement: The study was supported by funding provided by the World Health Organization (WHO). G.J. Fox was supported by a National Health and Medical Research Council (NHMRC) Career Development Fellowship (APP 1148372). The WHO secretariat developed the research question and provided input into the protocol. The funder had no role in data collection, data analysis, data interpretation or writing of the manuscript. Funding information for this article has been deposited with the Crossref Funder Registry.
- Received January 28, 2021.
- Accepted April 29, 2021.
- Copyright ©The authors 2021. For reproduction rights and permissions contact permissions{at}ersnet.org
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