SETTING: Five medical schools in three cities in Rio de Janeiro State, Brazil, with different tuberculosis (TB) incidence rates. OBJECTIVE: To evaluate the prevalence of the booster phenomenon and its associated factors in a young universally BCG-vaccinated TB-exposed population. DESIGN: A two-step tuberculin skin test (TST) was performed among undergraduate medical students. Boosting was defined as an induration > or =10 mm in the second TST (TST2), with an increase of at least 6 mm over the first TST (TST1). The association of boosting with independent variables was evaluated using multivariate analysis. RESULTS: Of the 764 participants (mean age 21.9 +/- 2.7 years), 672 (87.9%) had a BCG scar. The overall booster phenomenon prevalence was 8.4% (95%CI 6.5-10.6). Boosting was associated with TST1 reactions of 1-9 mm (aOR 2.5, 95%CI 1.04-5.9) and with BCG vaccination, mostly after infancy, i.e., after age two years (aOR 9.1, 95%CI 1.2-70.7). CONCLUSION: The prevalence of the booster phenomenon was high. A two-step TST in young BCG-vaccinated populations, especially in those with TST1 reactions of 1-9 mm, can avoid misdiagnosis as a false conversion and potentially reduce unnecessary treatment for latent TB infection.
SETTING: Five medical schools in three cities in Rio de Janeiro State, Brazil, with different tuberculosis (TB) incidence rates. OBJECTIVE: To evaluate the prevalence of the booster phenomenon and its associated factors in a young universally BCG-vaccinated TB-exposed population. DESIGN: A two-step tuberculin skin test (TST) was performed among undergraduate medical students. Boosting was defined as an induration > or =10 mm in the second TST (TST2), with an increase of at least 6 mm over the first TST (TST1). The association of boosting with independent variables was evaluated using multivariate analysis. RESULTS: Of the 764 participants (mean age 21.9 +/- 2.7 years), 672 (87.9%) had a BCG scar. The overall booster phenomenon prevalence was 8.4% (95%CI 6.5-10.6). Boosting was associated with TST1 reactions of 1-9 mm (aOR 2.5, 95%CI 1.04-5.9) and with BCG vaccination, mostly after infancy, i.e., after age two years (aOR 9.1, 95%CI 1.2-70.7). CONCLUSION: The prevalence of the booster phenomenon was high. A two-step TST in young BCG-vaccinated populations, especially in those with TST1 reactions of 1-9 mm, can avoid misdiagnosis as a false conversion and potentially reduce unnecessary treatment for latent TB infection.
Authors: Juliet N Sekandi; Sarah Zalwango; Allan K Nkwata; Leonardo Martinez; Robert Kakaire; Jane N Mutanga; Christopher C Whalen; Noah Kiwanuka Journal: Am J Trop Med Hyg Date: 2018-01-04 Impact factor: 2.345
Authors: L Pérez-Barbosa; J A Esquivel-Valerio; A C Arana-Guajardo; D Vega-Morales; J Riega-Torres; M A Garza-Elizondo Journal: Rheumatol Int Date: 2015-03-14 Impact factor: 2.631
Authors: Ana Paula C Marques; Sandra Maria V L Oliveira; Grazielli R Rezende; Dayane A Melo; Sonia M Fernandes-Fitts; Elenir Rose J C Pontes; Maria da Glória Bonecini-Almeida; Zoilo P Camargo; Rinaldo P Mendes; Anamaria M M Paniago Journal: Mycopathologia Date: 2017-06-23 Impact factor: 2.574
Authors: Maitreyi Murthy; Sumithra Selvam; Nelson Jesuraj; Sean Bennett; Mark Doherty; Harleen M S Grewal; Mario Vaz Journal: PLoS One Date: 2013-09-06 Impact factor: 3.240