这种病毒缺少其他更厉害的流感所有的一些蛋白质和氨基酸，其表现与一些常见的病毒株相似，而大部分人群对这些毒株都有了免疫力。

It lacks certain proteins and amino acids that would make it as deadly as other flus. And it appears similar enough to other common strains that most people may have some immunity.

youdao

这些年来我自下意识地采取一些措施切断毒源。例如，不让我的孩子进行免疫接种，因为疫苗药液里含有汞。

I've made some perceived radical decisions over the years such as not immunizing my children due to the mercury content in the immunization fluid given to babies.

youdao

之前与H1N1病毒有过接触史似乎是一个关键因素，可以让人识别出1976年的疫苗毒株并产生强烈的免疫应答，这就如同1976年的疫苗能让人对2009年H1N1病毒产生强烈免疫应答一样。

That prior encounter with H1N1 seemed to be the key to a robust recognition of the 1976 vaccine virus, just as having had the 1976 vaccine seems to produce a strong response to the 2009 H1N1 virus.

youdao

Here's where the intelligence of the immune system comes in, is that these cytotoxic T-cells that are generated only kill cells that have this signal on it.

免疫系统的聪明之处就在此,这些细胞毒T细胞,只能杀死具有特殊标记信号的细胞

耶鲁公开课 - 生物医学工程探索课程节选