Several studies have not been able to show that taking vitamin supplements in addition to a balanced diet helps to prevent disease.

VOA: special.2010.09.14

If you're trying to prevent a disease that only occurs at a rate of 20 per 100,000 people you have to give the vaccine to millions in order to see if the number goes down.

如果你尝试去防治一个,发病概率为十万分之二十人的疾病,那么就必须将疫苗分发给数百万人,以观察疫苗能否降低发病率

耶鲁公开课 - 生物医学工程探索课程节选

So, you're treating healthy people and you're trying to prevent them from getting a disease and you don't know who's going to get it.

所以,你处治的对象是健康人群,要使他们远离疾病,但你不知道谁会被感染

耶鲁公开课 - 生物医学工程探索课程节选

That is,it is better to eat vitamin-rich foods to prevent disease instead of eating them to cure a disease after it has developed.

VOA: special.2009.04.21

As we'll see in section today, a vaccine does not have to be totally perfect in order to prevent transmission of a disease, because when a disease enters a community its spread from one person to another.

有如我们今天看到的,疫苗不一定非要,绝对完美地阻止疾病的传播,因为当疾病侵入一个社区后,会在人群间传播

耶鲁公开课 - 生物医学工程探索课程节选

Most vaccines help prevent disease in children,but reaching children in remote rural areas is often a challenge especially in poorer and war-torn countries.

VOA: standard.2009.12.28

It was one man's vision that if just two drops, from a bottle like this one, could prevent children from getting the disease, that global eradication could be within reach.

VOA: standard.2010.08.02

and also intensify vaccination against all infectious agents, all viruses that are known to be strongly associated with the development of cancer. The government should increase its efforts to prevent illnesses with links to cancer, he says,such as hepatitis, a disease of the liver, and the human papillomavirus, which is transmitted during intercourse and is linked to cervical cancer.

VOA: standard.2010.06.16