Annual risk of tuberculous infection using different methods in communities with a high prevalence of TB and HIV in Zambia and South Africa

dc.contributor.authorShanaube, Kwame
dc.contributor.authorSisminidis, Charalambos
dc.contributor.authorAyles, Helen
dc.contributor.authorBeyers, Nulda
dc.contributor.authorSchaap, Ab
dc.contributor.authorLawrence, Katherine-Anne
dc.contributor.authorBarker, Annie
dc.contributor.authorGodfrey-Faussett, Peter
dc.date.accessioned2011-05-15T16:00:15Z
dc.date.available2011-05-15T16:00:15Z
dc.date.issued2009-11
dc.descriptionThe original publication is available at http:/www.plosone.org
dc.description.abstractBackground: The annual risk of tuberculous infection (ARTI) is a key epidemiological indicator of the extent of transmission in a community. Several methods have been suggested to estimate the prevalence of tuberculous infection using tuberculin skin test data. This paper explores the implications of using different methods to estimate prevalence of infection and ARTI. The effect of BCG vaccination on these estimates is also investigated. Methodology/Principal Findings: Tuberculin surveys among school children in 16 communities in Zambia and 8 in South Africa (SA) were performed in 2005, as part of baseline data collection and for randomisation purposes of the ZAMSTAR study. Infection prevalence and ARTI estimates were calculated using five methods: different cut-offs with or without adjustments for sensitivity, the mirror method, and mixture analysis. A total of 49,835 children were registered for the surveys, of which 25,048 (50%) had skin tests done and 22,563 (90%) of those tested were read. Infection prevalence was higher in the combined SA than Zambian communities. The mirror method resulted in the least difference of 7.8%, whereas that estimated by the cut-off methods varied from 12.2% to 17.3%. The ARTI in the Zambian and SA communities was between 0.8% and 2.8% and 2.5% and 4.2% respectively, depending on the method used. In the SA communities, the ARTI was higher among the younger children. BCG vaccination had little effect on these estimates. Conclusions/Significance: ARTI estimates are dependent on the calculation method used. All methods agreed that there were substantial differences in infection prevalence across the communities, with higher rates in SA. Although TB notification rates have increased over the past decades, the difference in cumulative exposure between younger and older children is less dramatic and a rise in risk of infection in parallel with the estimated incidence of active tuberculosis cannot be excluded. © 2009 Shanaube et al.en_ZA
dc.description.versionPublishers' Version
dc.format.extent10 p. : ill.
dc.identifier.citationShanaube, K, et al. 2009. Annual Risk of Tuberculous Infection Using Different Methods in Communities with a High Prevalence of TB and HIV in Zambia and South Africa. PLoS ONE, 4(11): e7749, doi:10.1371/journal.pone.0007749.en_ZA
dc.identifier.issn1932-6203 (online)
dc.identifier.issn0256-9574 (print)
dc.identifier.otherdoi:10.1371/journal.pone.0007749
dc.identifier.urihttp://hdl.handle.net/10019.1/11606
dc.language.isoen_ZA
dc.language.iso
dc.publisherPublic Library of Science (PLOS)
dc.rights.holderAuthors retain copyright
dc.subjectMedical care surveys -- Zambiaen_ZA
dc.subjectHIV Infections -- Transmission -- South Africaen_ZA
dc.subjectMedical care surveys -- South Africaen_ZA
dc.subjectTuberculous infections -- Vaccination -- Zambiaen_ZA
dc.subjectTuberculous infections -- Vaccination -- South Africaen_ZA
dc.subject.lcshTuberculin test -- Effectiveness -- Zambiaen_ZA
dc.subject.lcshTuberculin test -- Effectiveness -- South Africaen_ZA
dc.subject.lcshTuberculous infections -- Risk factors -- Zambiaen_ZA
dc.subject.lcshTuberculous infections -- Risk factors -- South Africaen_ZA
dc.subject.lcshTuberculosis -- Transmission -- South Africaen_ZA
dc.subject.lcshTuberculosis -- Transmission -- Zambiaen_ZA
dc.titleAnnual risk of tuberculous infection using different methods in communities with a high prevalence of TB and HIV in Zambia and South Africaen_ZA
dc.typeArticleen_ZA
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