Sterne J A, Rodrigues L C, Guedes I N
Department of Public Health Medicine, United Medical and Dental Schools, St Thomas's Hospital, London, UK.
Int J Tuberc Lung Dis. 1998 Mar;2(3):200-7.
To investigate whether the protective efficacy of bacille Calmette-Guérin (BCG) against tuberculosis decreases with time since vaccination.
A quantitative review of all 10 randomized trials of BCG against tuberculosis in purified protein derivative (PPD)-negative individuals, that presented data for discrete periods. For each trial, we derived log rate ratios for the annual change in the efficacy of BCG. We also compared efficacy in the first two years, and the first 10 years, to that in the rest of the trial.
There was considerable heterogeneity between trials in the annual change in the efficacy of BCG. In seven efficacy decreased overtime, while in three it increased. Average annual change in efficacy was not related to overall efficacy. Efficacy also varied between trials in the first two years after vaccination, at more than two years after vaccination and in the first ten years after vaccination. However the variation in efficacy between trials more than 10 years after vaccination was not statistically significant (P = 0.26). We therefore calculated that the average efficacy more than 10 years after vaccination was 14% (95% confidence interval -9% to 32%).
BCG protection can wane with time since vaccination. There is no good evidence that BCG provides protection more than 10 years after vaccination.
研究卡介苗（BCG）对结核病的保护效力是否会随接种后的时间推移而降低。
对所有10项针对结核菌素纯蛋白衍生物（PPD）阴性个体的卡介苗预防结核病的随机试验进行定量综述，这些试验提供了不同时间段的数据。对于每项试验，我们得出卡介苗效力年度变化的对数率比。我们还比较了前两年、前10年的效力与试验其余阶段的效力。
卡介苗效力的年度变化在各试验之间存在相当大的异质性。7项试验中效力随时间下降，而3项试验中效力上升。效力的平均年度变化与总体效力无关。在接种后的前两年、接种后两年以上以及接种后的前10年，各试验之间的效力也有所不同。然而，接种后10年以上各试验之间效力的差异无统计学意义（P = 0.26）。因此，我们计算出接种后10年以上的平均效力为14%（95%置信区间为-9%至32%）。
卡介苗的保护作用会随接种后的时间而减弱。没有充分证据表明卡介苗在接种后10年以上仍能提供保护。
