The prevalence of tuberculosis infection among Year 8 schoolchildren in inner Sydney in 1992

Abstract

Objective To determine the prevalence of tuberculosis (TB) infection in Year 8 schoolchildren (aged 12‐14 years) in Sydney. Design Cross‐sectional survey. Setting 22 inner city Sydney secondary schools. Participants 2290 Year 8 school children enrolled in 1992. Outcome measures Distribution of Mantoux test reaction size and proportion of children who were Mantoux positive (i.e., having Mantoux reaction >15mm with previous Bacille Calmette‐Guérin vaccination; >10mm without). Results Of the 2290 children, 1836 (81%) were screened and 1801 Mantoux reactions were read. Ten per cent of children were Mantoux positive — 27% of foreign‐born children and 2% of Australian‐born children (relative risk 16.7, 95% confidence interval 10.6‐26.4). Two children were found to have active TB disease. Conclusion There is a high prevalence of primary (non‐contagious) TB infection in children aged 12‐14 years in inner Sydney, mostly confined to children born overseas. Thus there is a large pool of infected children at risk of developing active (contagious) adult‐type TB disease in the future. This public health problem should be addressed by identification and treatment of those infected.

The burden of pneumonia in children: an Australian perspective

“…In a study of [12][13][14] year-old Sydney children, 2% of the Australianborn and 27% of the overseas-born children had a positive Mantoux test. 38 The risk of developing TB disease following latent infection may be extremely high in early childhood 39 and remains significant through later childhood and adulthood. 40 Active identification of latent TB in recent migrants to Australia, especially in children, although not universally performed, would seem prudent.…”

Transmission of tuberculosis from a seven‐year‐old child in a Sydney school

“…Our study of 5–12 year‐olds who were almost all Australian born found a Mantoux positivity rate of 13% at the school and 7% at the after‐school care centre. Since TB infection in these children and in the two prevalence surveys quoted above 15 , 16 was not associated with parental country of birth, an exposure to infection within the school setting was most likely. Third, no parents, teachers or other adults in contact with the school children had active TB disease, and no adults had contact with both the primary school and the after‐school care centre.…”

“…The extent of infectivity of a tuberculosis patient is known to be determined by the presence of a cough, the presence of positive sputum, and prolonged duration of symptoms 3 . Second, both the primary school and the after‐school care centre had higher Mantoux positivity rates than those reported for Australian‐born schoolchildren aged 5–7 and 12–14 years in inner Sydney, 2.8% and 2%, respectively (using the same definitions for Mantoux positivity) 15 , 16 . Our study of 5–12 year‐olds who were almost all Australian born found a Mantoux positivity rate of 13% at the school and 7% at the after‐school care centre.…”

“…Thus Mantoux positivity was assumed to be associated with the index case as there was no opportunity to assess conversions. However, since the Mantoux positivity rate among Australian born children (irrespective of birthplace of parents) from two recent surveys was less than 3%, 15 , 16 it was not considered necessary to survey the children twice to ascertain the conversion rate.…”

Prevalence of tuberculosis infection among primary school‐entry children in Sydney

“…At approximately 72 hours after injection, the diameter of the area of induration of the injection site was measured to the nearest millimetre using a ruler and the ballpoint technique. 6 Previous BCG testing was ascertained by clinical history and examination for BCG scars. A history of previous BCG vaccination, documentation of BCG vaccination or a visible BCG scar was taken to be evidence of previous BCG vaccination.…”