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You're listening to Shortwave from NPR.

Hey, shortwavers, science correspondent Nate Roth here, filling in for Emily and Regina.

Today we're going to talk about a global disease that's long-hammered, sub-Saharan Africa,

particularly hard, HIV.

Specifically, we're going to talk about a vaccine to fight HIV.

So Ari Daniel, for those who don't recognize your dulcetones, is a freelance science reporter.

And Ari, I hear there's a pretty remarkable backstory to this vaccine we're going to talk about.

That is correct.

Okay, so where do you want to start?

All right.

Right here, Nate, inside a lab at the National Institute for Communicable Diseases in Johannesburg, South Africa.

It's arrayed with, if you can picture it, half a dozen large green and white freezers.

These are the freezers that contain samples

that are the basis of everything we do in the lab.

This is Penny Moore.

She's a virologist at the University of at Buderstrand.

Our freezers are named after the seven dwarves.

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