We are repurposing the BCG vaccine, which had been used against TB for almost a century.

我们正在重新利用卡介苗，这种疫苗在近一个世纪前就被用来预防结核病。

And this is a pretty useful feature of IGRAs since BCG vaccine is given to a lot of children around the world to prevent disseminated TB.

这是IGRA很有用的一种特性，因为世界上很多小孩都接种过卡介苗，来预防TB在体内的播散。

These techniques allowed researchers to develop reliable and effective vaccines– first for smallpox, and again in 1921, when scientists developed the BCG vaccine to battle TB.

研究人员用这些技术研制出了可靠、有效的疫苗——首先是针对天花，然后在 1921 年，科学家又研发出了卡介苗，用于对抗肺结核。

Also, the IGRA is more specific to TB rather than other types of mycobacterial infections and is unlikely to be positive as a result of having BCG vaccine in the past, a vaccine that protects against TB.

而且IGRA对于TB来说有更高的准确性，而不会对其它类型的分枝杆菌的感染出现反应，且IGRA并不会对于曾经接种过卡介苗的患者出现阳性反应；卡介苗是一种抵抗肺结核的疫苗。