Seminar Presentation: How Vaccines Train Your Immune System

Right, let's begin. Priya, the floor is yours.

好，我们开始吧。Priya，请你来。

Thanks. Um, I'm a bit nervous, so bear with me.

谢谢。嗯，我有点紧张，请大家多包涵。

Today I'm going to explain how vaccines actually work.

今天我要讲讲疫苗到底是怎么起作用的。

So, have you ever done a fire drill at school?

那么，你们在学校参加过消防演习吗？

Ha, loads of times. Usually in the rain.

哈，好多次了。还老是下雨天。

Exactly! Nobody's in danger, but everyone practises.

没错！没有人有危险，但每个人都在练习。

Well, a vaccine is basically a fire drill for your body!

其实，疫苗基本上就是给身体做的一场消防演习！

Every germ carries tiny markers called antigens.

每种病菌身上都带有一种叫抗原的微小标记。

A vaccine shows your body those markers,

疫苗会把这些标记展示给你的身体，

using a weakened germ, a dead one, or just a piece of it.

用的是减弱的病菌、灭活的病菌，或者只是它的一小部分。

So you get the practice, without the real illness.

这样你就能练习，却不用真的生病。

And then, your immune system gets to work!

然后，你的免疫系统就开始干活了！

It makes antibodies that stick to the antigens,

它会制造能附着在抗原上的抗体，

and it creates something brilliant: memory cells!

还会产生一样很厉害的东西：记忆细胞！

If the real germ turns up later, they recognise it fast.

以后真正的病菌一来，它们很快就能认出来。

Your body fights back before you even feel ill!

你还没觉得不舒服，身体就已经反击了！

Sorry, can I ask something?

不好意思，我能问个问题吗？

Of course, go ahead.

当然，你问吧。

If memory cells last, why do we need boosters?

如果记忆细胞会一直在，为什么还要打加强针？

Honestly, why do I need a flu jab every single year?

说真的，为什么我每年都得打流感疫苗？

Hmm... good question. Let me think.

嗯……好问题。让我想想。

Well, for some vaccines, the memory slowly fades.

嗯，有些疫苗留下的记忆会慢慢减弱。

A booster is just a reminder for your immune system.

加强针只是给免疫系统提个醒。

And flu viruses change their antigens all the time.

而且流感病毒总是在改变它们的抗原。

So last year's practice doesn't match this year's flu.

所以去年的演习对不上今年的流感。

Oh, that actually makes sense!

哦，这样说还真有道理！

One last point: herd immunity.

最后一点：群体免疫。

When most people are protected, the germ can't spread easily.

当大多数人都受到保护时，病菌就不容易传播。

That protects newborn babies, and people who can't have vaccines.

这能保护新生儿，以及无法接种疫苗的人。

So, that's it! Thank you for listening.

好，就是这些！谢谢大家。

Excellent, Priya! The fire drill idea worked really well.

太棒了，Priya！消防演习的比喻用得非常好。

Just slow down a little at the start.

只是开头的时候稍微放慢一点。

Oh, thank you! Honestly, I was terrified.

哦，谢谢！说实话，我刚才吓坏了。

You didn't look it. Well done!

完全看不出来。讲得好！