Harlan Krumholz

So if you go to Wuhan right now, it's about 2%.

Now, 2% is very high if you have a public health emergency and it gets out in the population.

But remember, in Wuhan, there are some features.

That generally is the people admitted to hospital.

They're the ones they're testing.

So it might be much higher than expected.

And some of the evidence is saying when you bring in all the symptomatic and asymptomatic people together, the case fatality may drop 10 or 100-fold and be somewhere around about 0.2 to 1%.

Now, that's where the public health emergency comes in.

If you infect hundreds of millions of people, a lot of people are going to die.

but actually the individual risk is still very small, but the public health risk is very large.

My concern is that this early phase, day two to five, where you have very little symptoms.

And I think that's what we've seen in Brighton is you can move around the world quite easy.

In five days.

In five days.

And you turn up and you've infected four or five people.

And that's where you get this R0 approaching three, four and even higher in the asymptomatic people.

Once that happens, really the rabbit is out of the bag and you have to shift your focus and saying containment's over.

And in swine flu, that's what happened in effect.

It transmitted so quickly.

Then you have to start to move to the supportive measures and trying to understand how you instigate that effectively.