Because no vaccine protects 100 percent of kids who get it, epidemiologists rely on "herd immunity" to make sure enough kids are well enough protected to keep a disease from spreading.
因为没有疫苗100%保护那些接种过疫苗的小孩，但流行病学家却根据“群体免疫”确信小孩能够很好地受到保护而防止疾病的传播。
The success of any given vaccine depends on so-called herd immunity, in which a high rate of immunization in a population helps to protect those individuals who are not immune.
任何特定疫苗的成功都依赖于所谓的免疫屏障，即通过高比率的免疫人群来保护不免疫的个体。
Many of the childhood vaccinations rely on "herd-immunity" - a certain percentage of the population having the vaccine in order to protect those that do not, or cannot have it, from infection.
许多儿童疫苗依赖于“群体免疫”——一定比例的人口接种某些疫苗是为了预防那些没有接种或不能接种的人受到感染。
It is also why every few decades a flu strain appears with the genetic novelty to evade our herd immunity and wreak global havoc.
这也是为什么每过几十年就会出现一个流感株，它有着足够的基因改变来攻克人群的免疫，掀起全球范围的混乱。
The study also provided evidence of the so-called "herd immunity effect" in which unvaccinated older people benefit from the vaccination of children and infants.
该研究还提供了所谓“人群免疫效应”的证据，即接种了疫苗的婴幼儿使未接种过该疫苗的大龄人群受益。
By contrast several rich countries, including America, Britain, France and Italy, are below herd immunity.
与之相对的是，包括美国、英国、法国、意大利在内的发达国家低于群体免疫力的阈值。
In many counties, towns and nursery schools — within Washington state, Oregon, Vermont and California, especially-vaccination rates are now far below the herd-immunity level.
现在，许多县、镇以及托儿所(特别是华盛顿、俄勒冈、佛蒙特、加利福尼亚等州)，接种率远远低于群体免疫水平。
There was a very significant negative association between the attack rate and the herd immunity (P<0.01).
罹患率与流行前群体免疫呈非常显著的负相关（P<0.01）。
There was a very significant negative association between the attack rate and the herd immunity (P<0.01).
罹患率与流行前群体免疫呈非常显著的负相关（P<0.01）。
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