A bomb that killed hundreds of thousands of people.

A scientist who wanted it made, but then didn't want it to be used.

My own grandfather and a picture of a mushroom cloud.

The Bomb, a brand new podcast from the BBC World Service, available now.

Do you have a list, a roll call of things you're looking forward to doing again when the pandemic of 2020 is finally over?

I do.

But before you or I will be able to do these things we miss so much,

we'll need protection against a novel coronavirus,

ideally a vaccine that can reach more than 7 billion people.

This is a mammoth ambition, which comes with a host of practical problems, political collisions and moral dilemmas.

And the idea that this discovery will enable us to rapidly return to what we knew as normal is a simple, understandable desire, but one which underestimates the enormous challenges in a complex process.

Welcome to the documentary on the BBC World Service.

I'm Sandra Cantall, and you're listening to Part 1 of Vaccines, Money and Politics.

In this two-part series, you'll hear about the many challenges involved in a global vaccination program.

Some you can imagine. Others may surprise you, like they've done me.

I don't think many of us realize what a difficult effort this is going to be. The average length of time it takes to make a vaccine from having a

virus in hand to a commercial product is on average about 15 to 20 years.

I was part of a team that created the rotavirus vaccine.

That was a 26-year effort, and that is not atypical.

Dr. Paul Offutt is a pediatrician and the director of the Vaccine Education Program at Children's Hospital of Philadelphia in Pennsylvania.

He's also written several books on the subject of vaccines.

You can do it by taking a virus and killing it, the way that we make the inactivated polio vaccine.

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