Tuberculosis control in South African gold mines: mathematical modeling of a trial of community-wide isoniazid preventive therapy.
Bottom Line: A recent major cluster randomized trial of screening, active disease treatment, and mass isoniazid preventive therapy for 9 months during 2006-2011 among South African gold miners showed reduced individual-level tuberculosis incidence but no detectable population-level impact.We found the following: 1) The model suggests that a small proportion of latent infections among human immunodeficiency virus-positive people were cured, which could have been a key factor explaining the lack of detectable population-level impact. 2) The optimized implementation increased impact by only 10%. 3) Implementing additional interventions individually and in combination led to up to 30% and 75% reductions, respectively, in tuberculosis incidence after 10 years.Tuberculosis control requires a combination prevention approach, including health systems strengthening to minimize treatment delay, improving diagnostics, increased antiretroviral treatment coverage, and effective preventive treatment regimens.
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Mentions: These findings were consistent across parameter values that were resampled using the likelihood of the incidence as the weight (Figure 5). The percentage of infections that were cured by 6 months of IPT was low for HIV-positive miners (median, 13.5%; 95% credible range, 0.7−66) but in a wide range for those who were HIV-negative (median, 55%; 95% credible range, 10–96), as was the IPT-derived protection against reinfection (median, 25%; 95% credible range, 0.4–75 for HIV-positive miners). The impact on the measured incidence and prevalence associated with these values was 14% (95% credible range, 11–17) and 9% (95% credible range, 6–12), respectively. Using the likelihood of the prevalence data as the weight gave similar findings (Web Figure 16).Figure 5.