Annual risk of tuberculosis infection in Sri Lanka: a low prevalent country with a high BCG vaccination coverage in the South-East Asia Region
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Abstract
Introduction: Despite its simplicity, efficiency and reliability, Sri Lanka has notused the Annual Risk of Tuberculosis Infection (ARTI) to assess the prevalenceand efficiency of tuberculosis (TB) control. Hence, a national tuberculin surveywas conducted to estimate the ARTI.Materials and Methods: A school‑based, cross‑sectional tuberculin survey of4352 children aged 10 years irrespective of their BCG vaccination or scar statuswas conducted. The sample was selected from urban, rural and estate strata usingtwo‑stage cluster sampling technique. In the first stage, sectors representing threestrata were selected and, in the second stage, participants were selected from120 clusters. Using the mode of the tuberculin reaction sizes (15 mm) and themirror‑image technique, the prevalence and the ARTI were estimated.Results: The prevalence of TB estimated for urban, rural and estate sectors were13.9%, 2.2% and 2.3%, respectively. The national estimate of the prevalenceof TB was 4.2% (95% CI = 1.7-7.2%). ARTI for the urban, rural and estatesectors were 1.4%, 0.2% and 0.2%, respectively, and the national estimate was0.4% (95% CI = 0.2-0.7%). The estimated annual burden of newly infected orre‑infected TB cases with the potential of developing into the active disease(400/100 000 population) was nearly 10‑fold higher than the national new casedetection rate (48/100 000 population).Conclusion: The national estimate of ARTI was lower than the estimates for manydeveloping countries. The high‑estimated risk for the urban sector reflected theneed for intensified, sector‑specific focus on TB control activities. This underscoresthe need to strengthen case detection. Repeat surveys are essential to determinethe annual decline rate of infection.Citation
Pushpa Ranjan Wijesinghe, Paba Palihawadana, Sunil De Alwis & Sudath Samaraweera. (2013). Annual risk of tuberculosis infection in Sri Lanka: a low prevalent country with a high BCG vaccination coverage in the South-East Asia Region. WHO South-East Asia Journal of Public Health, 2 (1), 34 - 40. World Health Organization. Regional Office for South-East Asia. https://iris.who.int/handle/10665/329768
Journal
WHO South-East Asia Journal of Public Health, 2 (1): 34 - 40ISSN
2224-3151 (Print)2304-5272 (Electronic)