The virus is not killed so It's a live virus, which is actually going to infect your intestinal system and reproduce.

病毒没有被杀死,那么它就是活性病毒,也就意味着它将会,侵入你的肠道系统并且会繁殖

耶鲁公开课 - 生物医学工程探索课程节选

You could imagine that you've got virus that's propagating inside your cells, making more and more virus, your immune system really responds well to that.

你可以想象,病毒在你的体细胞内繁殖,数量越来越多,你的免疫系统对此反应非常之强烈

耶鲁公开课 - 生物医学工程探索课程节选

Because it infects your cells and reproduces, your immune system responds much more vigorously.

由于它会感染你的细胞并且繁殖,所以你的免疫系统会有很强烈的反应

耶鲁公开课 - 生物医学工程探索课程节选