How Do Vaccines Work? | COLOSSAL QUESTIONS

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人体的免疫系统是一个庞大的军队,由免疫器官、免疫组织、免疫细胞和免疫分子组成。免疫系统的任务是防止外界病原体的入侵,清楚已入侵病原体及其他有害物质。疫苗接种相当于让免疫系统在真正遇到敌人之前进行的一次军事演练,通过注射减低活性、灭活或含有病原片段的病原体到体内来训练这支队伍。

No one likes to get shots, but most of us get them when we're kids in the form of vaccines.

So what are they?

What's in a vaccine, and how do they work?

Let's find out on today's episode of-- Colossal Questions.

Do you know anyone who has polio?

How about smallpox, measles, mumps?

It's unlikely that you do.

That's because these diseases have been all but eliminated by those prickly, pointy shots called vaccines we get as kids.

Take polio, for example.

This infectious disease caused multiple epidemics in the US alone between the late 1800s and the 1940s when a vaccine was more widely available in the country.

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