Seminar Presentation: How Vaccines Train Your Immune System

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

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

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

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

Ha, loads of times. Usually in the rain.

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

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

Every germ carries tiny markers called antigens.

A vaccine shows your body those markers,

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

So you get the practice, without the real illness.

And then, your immune system gets to work!

It makes antibodies that stick to the antigens,

and it creates something brilliant: memory cells!

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

Your body fights back before you even feel ill!

Sorry, can I ask something?

Of course, go ahead.

If memory cells last, why do we need boosters?

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

Hmm... good question. Let me think.

Well, for some vaccines, the memory slowly fades.

A booster is just a reminder for your immune system.

And flu viruses change their antigens all the time.

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

Oh, that actually makes sense!

One last point: herd immunity.

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

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

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

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

Just slow down a little at the start.

Oh, thank you! Honestly, I was terrified.

You didn't look it. Well done!