It might suggest that you could convert all the work to heat.

它暗示我们可以把所有的功转化为热,但是热力学第二定律说。

麻省理工公开课 - 热力学与动力学课程节选

So, it's more effective because it's a live virus but it's a little bit more concerning because it's a live virus as well, in that you trust that it's attenuated but could it convert back to a virulent form or a form that caused a disease.

因此,口服疫苗更加有效,因为它是活性病毒,但又是因为这一点,人们也存有更多顾虑,当它处于减毒状态时你会信任它,但是它会不会转变回,强毒壮态或者致病状态呢

耶鲁公开课 - 生物医学工程探索课程节选