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Tuberculin skin test conversion and primary progressive tuberculosis disease in the first 5 years of life: a birth cohort study from Cape Town, South Africa

L. Martinez, D. L. le Roux, W. Barnett, A. Stadler, M. Nicol, H. Zar

The Lancet Child & Adolescent Health, 2018

46 citations

Abstract

Summary Background Tuberculosis is a leading cause of global childhood mortality. However, the epidemiology and burden of tuberculosis in infancy is not well understood. We aimed to investigate tuberculin skin test conversion and tuberculosis in the Drakenstein Child Health study, a South African birth cohort in a community in which tuberculosis incidence is hyperendemic. Methods In this prospective birth cohort study, we enrolled pregnant women older than 18 years who were between 20 and 28 weeks' gestation and who were attending antenatal care in a peri-urban, impoverished South African setting. We followed up their children for tuberculosis from birth until April 1, 2017, or age 5 years. All children received BCG vaccination at birth. Tuberculin skin tests were administered to children at 6, 12, 24, 36, 48, and 60 months of age, and at the time of a lower respiratory tract infection. An induration reaction of 10 mm or more was considered to be a tuberculin skin test conversion. To prevent boosting, we censored children with a reactive, negative tuberculin skin test. Findings Among 915 mother–child pairs (201 [22%] HIV-positive mothers and two [<1%] HIV-positive children), 147 (16%) children had tuberculin skin test conversion, with increasing cumulative hazard with age (0·08 at 6 months, 0·17 at 12 months, 0·22 at 24 months, and 0·37 at age 36 months). For every 100 child-years, the incidence was 11·8 (95% CI 10·0–13·8) for tuberculin skin test conversion, 2·9 (2·4–3·7)…

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Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence.

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