If I happen to have some other infectious disease, then not only would you passing the protection to smallpox, but you'd be passing that disease among the population as well.

如果正好还有其他传染病,那不仅会传播对天花的免疫能力,也在人群中传播其它传染病

耶鲁公开课 - 生物医学工程探索课程节选

It's contagious, that is, it's transferred to other persons or objects, depending on how receptive they are--perhaps by physical touch, perhaps in the case of severe impurity by sharing an enclosed space, by being together under an overhanging roof, tent.

它会传染给另一个人，另一个物体，这取决于它们的接受度，也许是通过肢体接触，也许是因为呆在一个与世隔绝的空间里，同在一个屋檐下。

耶鲁公开课 - 旧约导论课程节选

Now, the problem, or one of the challenges with clinical trials of vaccines is that you have to enroll a lot of patients into clinical trials because only a few are going to get sick in any case, only 20 out of 100,000.

现在的问题是,这也是疫苗临床试验的挑战之一,临床试验必须包括足够多的病人,毕竟只有一小部分人会被传染,十万人里面只有二十人被传染

耶鲁公开课 - 生物医学工程探索课程节选