You're listening to Shortwave from NPR.

The Centers for Disease Control and Prevention estimates that anywhere from 24,000 to 81,000 people died from the flu during this past flu season.

Hundreds of thousands more were hospitalized and millions were infected. And this is a moderate season.

In the event of a whole flu pandemic, those numbers could be much higher.

There is more than 100 potential pandemic flu viruses that could start the pandemic.

That's Adolfo Garcia-Sastri, a viral immunologist at the ICANN school of medicine at

Mount Sinai in New York.

He's working on a vaccine that could not only protect people from a pandemic flu virus,

but all flu viruses.

No more annual flu shots.

He calls it a universal flu vaccine.

This shot that we are working on

will protect not only against seasonal influenza, not only of this year, not only against next year

and next year and next year and next year and this year, but also will prevent pandemic influenza

from an animal reservoir.

A vaccine like this hasn't been possible before, because the virus that causes the flu, influenza, mutates every year, evading the previous year's vaccine.

But he says, the virus cannot change completely. If not, we will not recognize it as influenza.

And Adolfo and his team are working on a vaccine that can target all versions of the influenza virus,

past, present and future, if they can find the resources.

Today on the show, the science behind a vaccine against all flus and what scientists need to make it a reality.

I'm Regina Barber, and you're listening to Shortwave, the science podcast from NPR.

Okay, Adolfo, what about the flu virus impacts why we need a yearly vaccine?

...