TY - JOUR T1 - RIsk of active tuberculosis among schoolchildren in hong kong AU - Leung C, Yew W, Chang K, et al Y1 - 2006/03/01 N1 - 10.1001/archpedi.160.3.247 JO - Archives of Pediatrics & Adolescent Medicine SP - 247 EP - 251 VL - 160 IS - 3 N2 - Objective  To estimate the risk of active tuberculosis (TB) and its implication on preventive treatment among BCG-vaccinated schoolchildren.Design  Cohort and case-control designs.Setting  Community settings in a high-prevalence area.Participants  Children in primary school. The main exposure was their tuberculin response.Main Outcome Measures  Of 94 928 primary schoolchildren tuberculin tested during a routine school revaccination program in 1999, 656 with a tuberculin response at 20 mm or more were followed up prospectively through the territory-wide TB registry up to December 31, 2003, for the development of TB. In a separate case-control analysis, the tuberculin responses of children who subsequently had active TB (at the age of 10-15 years) were compared with those of their sex- and age-matched classmates to ascertain the relative risks of TB for different tuberculin reaction categories. The absolute and relative risks were applied to the 1999 cohort for estimating the incidence of TB among different tuberculin reactors.Results  The annual incidence (95% confidence interval) of active TB was estimated to be 13.4 (5.6-40.6) per 100 000 for the entire cohort and 7.5 (2.4-24.5), 7.5 (1.7-32.0), 16.0 (4.4-57.2), 92.6 (26.6-320.2), and 340.6 (163.3-626.4) per 100 000 for children with a tuberculin reaction at 0 to 4, 5 to 9, 10 to 14, 15 to 19, and 20 mm or more, respectively. By using 10 mm as the cutoff, 482 (95% confidence interval, 163-1391) children have to be treated to prevent a single case of active TB within 5 years. Treatment will cover 17.5% of the cohort, but prevent only 54.1% of all active TB cases.Conclusion  It is desirable to reexamine the existing screening method for BCG-vaccinated children from high-prevalence countries. SN - 1072-4710 M3 - doi: 10.1001/archpedi.160.3.247 UR - http://dx.doi.org/10.1001/archpedi.160.3.247 ER -