From The New York Times, I'm Michael Vabarro. This is a daily.

It's quickly becoming the most dominant and dangerous strain of the coronavirus,

globally and in the U.S.

Today, science reporter Carl Zimmer, on everything you need to know about the Delta variant.

It's Tuesday, July 6.

So, Carl, I want to start this conversation with a bit of a disclosure, which is that

we have been debating for some time on the daily team weather and when to make an episode about

the Delta variant and if it would be alarmist to devote entire episode to it.

And it now feels like over the past week or so, there was a turning point and this story of

the Delta variant has become indisputably important and dangerous and something we should devote

to an episode too. Well, I couldn't agree more. Welcome to the Delta Club,

as long as I say. I mean, for those of us who have a thing for variants, we've had our ION Delta

for a long time and it's doing exactly what people warned it would do. So here we are.

Well, it's not a club I ever wanted to join, but I appreciate your invitation.

What exactly is it doing? I mean, at the highest possible level, tell us what this variant really is.

This variant is sweeping across the world and it is threatening to put us into an entirely new

stage of the pandemic. But to appreciate just how worried scientists are about Delta, you actually

have to step back and take a look at the variant that we were worried about before, which was alpha.

So in December, scientists in the UK discovered that there was this variant called alpha,

which seems to have originated somewhere there in England. And it was spreading very quickly.

And the scientists eventually determined that it was roughly 50% more transmissible

than earlier variants. Right. This is what we came to know as the British variant and it was

...