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OBJECTIVE: Paediatric laboratory reference intervals used in Africa and Asia may be derived from historical intervals of predominantly Caucasian infants in Europe or North America. These intervals may therefore not be compatible with the range of normality for developing country populations. We aimed to compare haematology and biochemistry parameters in healthy South African infants with local laboratory reference intervals. METHODS: We compared the baseline haematology and biochemistry results of 634 (316 male and 318 female) HIV-unexposed infants, aged 3-6 months, living in a rural area of the Western Cape Province, South Africa, against laboratory reference intervals supplied by the South African National Health Laboratory Services (NHLS). We calculated the percentage of observed values out of bound (in terms of lower and upper limits) compared to laboratory reference intervals. RESULTS: Of the 634 healthy infants screened, 316 (49.84%) were male and 318 (50.16%) female. A majority (91.05%) had platelet counts above the laboratory reference interval upper limit (350 × 109 cells/l), while over half, 54.85% and 56.98% had mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) values below the lower limits of 77.0-105.0 fl and 26.0-34.0 pg, respectively. A small proportion were outside the reference limits for haematocrit, namely 15.71% below and 7.14% above the normal limits of 0.31-0.38 l/l. For male and female infants, 33.65% and 18.04% of alkaline phosphatase (ALP) values and 7.01% and 14.56% of alanine transaminase (ALT) values were above the upper limits, respectively. For male infants, 10.83% of gamma-glutamyl transferase (GGT) values, and for female infants, 31.11% of GGT values were below the lower limits of 12 U/l for males and 15 U/l for females. We observed no significant deviations (>10% out of bound) from NHLS reference intervals in the remaining haematology and biochemistry parameters measured. CONCLUSIONS: Haematology and biochemistry parameters in apparently healthy South African infants deviate frequently from national laboratory reference intervals, including abnormalities consistent with subclinical hypochromic microcytic anaemia. It is important that clinical laboratory reference intervals for children are derived locally, rather than being adopted from Caucasian norms in developed countries, because clinical trials of vaccines, drugs and diagnostics are increasingly conducted in sub-Saharan Africa.
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Química Clínica/normas , Hematología/normas , Bienestar del Lactante , Estándares de Referencia , Recuento de Células Sanguíneas/normas , Femenino , Humanos , Lactante , Masculino , Vigilancia en Salud Pública , Valores de Referencia , SudáfricaRESUMEN
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Tuberculosis Latente/epidemiología , Instituciones Académicas , Adolescente , Distribución por Edad , Niño , Estudios de Cohortes , Femenino , Humanos , Tuberculosis Latente/diagnóstico , Tuberculosis Latente/transmisión , Masculino , Prevalencia , Factores Socioeconómicos , Sudáfrica/epidemiología , Adulto JovenRESUMEN
BACKGROUND: The Xpert MTB/RIF test shortens the time to microbiological confirmation of pulmonary tuberculosis (TB) under research conditions. OBJECTIVE: To evaluate the field impact of Xpert MTB/RIF rollout on TB diagnostic yield and time to treatment in a South African (SA) community. METHODS: We compared TB investigation outcomes for 6-month calendar periods before and after Xpert MTB/RIF rollout in a semi-rural area of SA. The proportion of adult patients who tested positive by sputum smear microscopy, liquid culture or Xpert MTB/RIF and the proportion of positive sputum smear, liquid culture or Xpert MTB/RIF tests were compared. Secondary outcomes included time to laboratory diagnosis and treatment initiation. Data were collected from the National Health Laboratory Service database and from the Western Cape Provincial Department of Health TB register. RESULTS: Regional rollout of Xpert MTB/RIF testing occurred in 2013. Of the 15 629 patients investigated in the post-rollout period, 7.9% tested positive on GeneXpert, compared with 6.4% of the 10 741 investigated in the pre-rollout period who tested positive by sputum smear microscopy (p<0.001). Median laboratory processing time was <1 day for Xpert MTB/RIF (interquartile range (IQR) 0 - 1) compared with 1 day (IQR 0 - 16) for sputum smear microscopy (p=0.001). The median time to TB treatment initiation was 4 days (IQR 2 - 8) after rollout compared with 5 days (IQR 2 - 14) before (p=0.001). CONCLUSIONS: Patients investigated for suspected pulmonary TB were more likely to be diagnosed after rollout of Xpert MTB/RIF testing, although the benefit to diagnostic yield was modest, and Xpert MTB/RIF testing was associated with a marginal improvement in time to treatment initiation.
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SETTING: South Africa. OBJECTIVE: To evaluate the long-term effectiveness of infant modified vaccinia Ankara virus-expressing antigen 85A (MVA85A) vaccination against tuberculosis (TB). DESIGN: We analysed data from a double-blind randomised placebo-controlled Phase 2b MVA85A infant TB vaccine trial (2009-2012), with extended post-trial follow-up (2012-2014). Isoniazid preventive therapy (IPT) was provided by public health services according to national guidelines. The primary outcome was curative treatment for TB disease. Survival analysis and Poisson regression were used for study analysis. RESULTS: Total follow-up was 10 351 person-years of observation (pyo). Median follow-up age was 4.8 years (interquartile range 4.4-5.2). There were 328 (12%) TB cases. TB disease incidence was 3.2/100 pyo (95%CI 2.8-3.5) overall, and respectively 3.3 (95%CI 2.9-3.9) and 3.0 (95%CI 2.6-3.5)/100 pyo in the MVA85A vaccine and placebo arms. A total of 304 children (11%) received IPT, with respectively 880 and 9471 pyo among IPT and non-IPT recipients. There were 23 (7.6%) TB cases among 304 IPT recipients vs. 305 (12.9%) among 2374 non-IPT recipients (P = 0.008). IPT effectiveness was 85% (95%CI 76-91). CONCLUSION: Extended follow-up confirms no long-term effectiveness of infant MVA85A vaccination, but a six-fold reduction in TB risk can be attributed to IPT. National TB programmes in high TB burden countries should ensure optimal implementation of IPT for eligible children.