Welcome to the inquiry on the BBC World Service with me, Kavita Puri. Each week, one question, four expert witnesses and an answer.

In Melbourne, Australia, a woman is wearing a space suit.

Air is piped into the heavy cumbersome outfit.

She's literally in her own bubble.

She's a scientist and is handling a viral agent that has caused tens of thousands of deaths across the world

and brought great countries to their knees.

She's injecting a ferret with COVID-19. It's a highly dangerous task.

She's one of the many scientists around the world working on the early stages of a vaccine.

It's a race against time.

A vaccine is the one thing we know that can stop someone getting the virus

and preventing it spreading. So this week we ask, why is it taking so long to develop a COVID-19 vaccine? Part 1, the Valley of Death.

I was in Singapore in 2003 when SARS hit us so I was a frontline worker there and then I

continued to work on emerging infectious diseases ever since.

Our first expert witness Analice Wilder Smith,

Professor of Emerging Infectious Diseases

at the London School of Hygiene and Tropical Medicine.

Born in Holland, she now lives in Switzerland.

That's my life's career, so the past now almost 30 years I've spent in infectious diseases, mainly as a clinician and now more and more in public health.

She spends a lot of time working on vaccines for infectious diseases. On average... on average can you say how long does it take for a vaccine to get to market.

All the latest vaccines took at least 10 years.

So obviously during an outbreak like this one,

there is an incredible political will

...