But herd immunity works only when nearly the whole herd joins in.
2017年高考英語北京卷 閱讀理解 閱讀C 原文
Herd immunity works well when the whole neighborhood is involved in.
2017年高考英語北京卷 閱讀理解 閱讀C 題設(shè)
This is called "herd immunity", which protects the people who get hurt easily, including those who can't be vaccinated for medical reasons, babies too young to get vaccinated and people on whom the vaccine doesn't work.
2017年高考英語北京卷 閱讀理解 閱讀C 原文
When some refuse vaccination and seek a free ride, immunity breaks down and everyone is in even bigger danger.
2017年高考英語北京卷 閱讀理解 閱讀C 原文
The study also found that the genes for smell were something shared in friends but not genes for immunity.