Now, the polio vaccine that Salk produced was very effective, but it required a fairly large dose of the vaccine and it had to be injected into the arms of children.

索尔克生产的小儿麻痹症疫苗效果显著,但是,该疫苗的单支注射剂量非常大,而且必须通过小孩的手臂进行注射

耶鲁公开课 - 生物医学工程探索课程节选

So, even if the cost is small, $10 a dose, it quickly amounts to a large amount of money.

因此,即使单只成本很小,可能只有十美元,但是这很快就会累积成为很大的金额

耶鲁公开课 - 生物医学工程探索课程节选

Give enough of the vaccine so you have a dose for everybody in the world, or a large fraction of the people.

疫苗的数量,足以让世界上每个人都接种一支,或者让绝大多数人都能接种一支

耶鲁公开课 - 生物医学工程探索课程节选