IJE Advance Access originally published online on September 28, 2006
International Journal of Epidemiology 2006 35(6):1447-1454; doi:10.1093/ije/dyl213
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Article |
Is tuberculin skin testing useful to diagnose latent tuberculosis in BCG-vaccinated children?
1 Instituto Nacional de Salud Pública (INSP), 7a. Cerrada de Fray Pedro de Gante No. 50 Col. Sección XVI, Deleg. Tlalpan, C.P. 14000, Mexico, D.F., Mexico.
2 Instituto Nacional de Enfermedades Respiratorias (INER), Calzada Tlalpan 4502, Col. Sección XVI, Delegación Tlalpan, C.P. 14080, Mexico, D.F., Mexico.
3 Instituto Nacional de Ciencias Médicas y Nutrición (INCMNSZ), Vasco de Quiroga XX, Col. Sección XVI, Delegación Tlalpan, C.P. 14000, Mexico, D.F., Mexico.
4 University of California, Davis School of Medicine, One Shields Avenue Davis, CA 95616, USA.
5 Bill and Melinda Gates Foundation, Seattle, Washington, USA
* Corresponding author. Tuberculosis Unit, 7a. Cerrada de Fray Pedro de Gante No. 50 Col. Sección XVI, Deleg. Tlalpan, C.P. 14000, Mexico, D.F., Mexico. E-mail: garcigarml{at}gmail.com
| Abstract |
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Background The tuberculin skin test (TST) is the most commonly used tool to detect infection with Mycobacterium tuberculosis. We sought to determine whether tuberculin skin testing is useful to detect latent infection by M. tuberculosis in a population that was vaccinated with the Bacille Calmette Guérin (BCG) vaccine.
Methods We performed a cross-sectional study during October 2000February 2001, enrolling first and sixth graders from a random, stratified sample of public elementary schools in Orizaba, Veracruz, Mexico. We assessed the relationship between sociodemographic and epidemiological information, BCG scars, and TST reactivity.
Results There were 858 children enrolled in the study with a completed questionnaire and TST result. The prevalence of a positive TST result (
10 mm) was 12.4%. Controlling for BCG scar, age, and other characteristics, close contact with pulmonary tuberculosis patients (odds ratio 6.56, 95% confidence interval 2.0521.07, P = 0.001) was independently associated with TST reactivity.
Conclusions TST results helped identify children in a BCG-vaccinated population who had recent exposure to persons with pulmonary tuberculosis, were probably infected with M. tuberculosis, and could benefit from treatment for their latent tuberculosis infection.
Keywords Mycobacterium tuberculosis, latent infection, tuberculin skin test, Bacille Calmette Guérin (BCG) vaccine
Accepted 30 August 2006