You're listening to Shortwave from NPR.

NPR is science correspondent Jeff Brumfield.

I understand you want to have a little talk with us today.

That's right, Maddie.

So back in August of last year, you and I chatted about something called herd immunity.

Yes, herd immunity.

This idea that if enough people are immune to the coronavirus, either through vaccination

or infection, this disease will run out of places to spread.

It'll burn out.

Yeah, that's right.

I don't know how much of that conversation you remember.

Well, I certainly remember you getting very excited once you learned about it from a YouTube

video of a guy in his backyard.

Oh, those were some good times.

We spent a lot of time talking about what made herd immunity hard to achieve and how

we probably weren't going to get there.

And after that conversation, I kind of thought it might go away, but it turns out the way

it is on for enough doses to achieve herd immunity.

In fact, if you're worried, are you about the US reaching herd immunity?

We need to get the vaccine before we can say herd immunity.

I think we will actually reach herd immunity.

When?

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