Welcome to Public Health On Call, a podcast from the Johns Hopkins Bloomberg School of Public Health.

I'm Joshua Sharfstein, Vice Dean for Public Health Practice and Community Engagement,

and a former health commissioner here in Baltimore.

Our goal is to bring evidence and experience to illuminate critical public health issues.

If you have questions or ideas for us, please send an email to public health question at jhh.edu.

That's public health question at jh.hu.edu for future podcast episodes.

Hi, I'm Lindsay Smith-Rogers, producer of public health on call.

Today, Stephanie Desmond welcomes back Johns Hopkins virologist, Dr. Andy Peckosch.

They discuss why COVID's Omicron variant keeps mutating, what this means in the race to end the

pandemic, and how a new kind of vaccine this fall may offer

better protection. Let's listen. Andy Pecos, thanks so much for joining me. Oh, always a pleasure.

So today I want to talk about COVID and its variance and I guess it's sub-variance, which is what we're dealing with now.

So we keep calling this Omicron, these new sub-variants, and they're very different from one another.

Talk to me about where we sit today.

Yeah, so when Omicron first emerged, right from the beginning, we knew there were a couple of different versions of it.

And as viruses do, when a variant emerges, it never stops mutating and changing, so they've continued to change.

Omicron being a really transmissible virus, it just amplifies then how quickly we see these

mutations emerge.

And so we went from one Omicron to now there's essentially five versions of Omicron with

a few other tweaks in there as well.

And what's important is that each of these are showing a little bit of a different property.

They're different from each other.

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