Levy M Z, Medeiros E A S, Shang N, Soares M C S, Homenko A S, Almeida R M, Garrett D O, Roth V R, Jarvis W R, Wells C D, Binkin N, Laserson K F
Program in Population Biology, Evolution, and Ecology, Emory University, Atlanta, Georgia, USA.
Int J Tuberc Lung Dis. 2005 Jul;9(7):771-6.
A major university in São Paulo, Brazil, where vaccination against tuberculosis (TB) with bacille Calmette-Guerin (BCG) was routinely offered to first-year medical and nursing students.
To estimate the probability of negative tuberculin skin test (TST) results over a 4-year period following BCG revaccination, and to evaluate the effect of factors associated with reversion.
Students were enrolled in 1997, initially given a two-step TST, and were retested annually or biannually for the duration of the study. Data on TB exposures and potential risk factors for TST negativity and reversion were collected through annual surveys. A linear mixture survival model was used to estimate the probability of negative TST results over time.
Of 159 students, an estimated 20% had a negative TST result despite revaccination, and a further 31% reverted to negative over 4 years of follow-up. No cofactors significantly affected the probability of reversion.
Overall, in the absence of reported exposure to Mycobacterium tuberculosis, 51% of students revaccinated upon entering nursing or medical school would have a negative TST result by the time they begin their internships. In this recently vaccinated population, reversion was common, suggesting that annual TST screening may remain a useful tool.
巴西圣保罗的一所主要大学，该校会定期为一年级医学和护理专业学生提供卡介苗（BCG）结核病疫苗接种。
评估卡介苗复种后4年内结核菌素皮肤试验（TST）结果为阴性的概率，并评估与TST结果转阴相关因素的影响。
1997年招募学生，最初进行两步TST检测，并在研究期间每年或每半年进行一次重新检测。通过年度调查收集结核病暴露情况以及TST结果为阴性和转阴的潜在风险因素的数据。使用线性混合生存模型来估计随时间推移TST结果为阴性的概率。
159名学生中，估计有20%的学生尽管进行了复种，TST结果仍为阴性，在4年的随访中，另有31%的学生TST结果转为阴性。没有辅助因素对TST结果转阴的概率有显著影响。
总体而言，在没有报告接触结核分枝杆菌的情况下，进入护理或医学院时进行复种的学生中，51%在开始实习时TST结果会为阴性。在这个近期接种过疫苗的人群中，TST结果转阴很常见，这表明每年进行TST筛查可能仍然是一种有用的工具。
