Study setting
Our study was conducted in the Ravensmead/Uitsig (R/U)
community in the Tygerberg District, Western Cape Province,
South Africa, where the incidence of culture-confirmed tuberculosis
in children aged (13 years was 407/100 000 in 2004.15
The total tuberculosis notification rate was 841 per 100 000 in
2002,16 and the prevalence of HIV among patients with
tuberculosis was 8% in 2005 (Cape Town City Health). R/U
is a well-characterised poor urban community of predominantly
mixed ethnicity, with both formal and informal housing
structures, often on the same residential property. Multiple
families therefore often share the same residential address.
There is a high level of ongoing M tuberculosis transmission at
the household and community level.17 In 2005 the calculated
annual risk of M tuberculosis infection in R/U assessed through
community-based school surveys was 3.5% among children
aged 6–14 years, with 34.4% of children having a positive TST
(>10 mm) (unpublished findings). BCG vaccine (Danish strain;
1331, Statens Serum Institute (SSI), Copenhagen, Denmark) is
routinely given at birth.