Thread by @juliaoftoronto

Is China's #coronavirus outbreak going to grow into the big one?

While the signs are worrying, it's too early to tell.

We don't know how fast the disease spreads, or how many people are really sick/dying among the infected. What we can say... 1/8

vox.com/2020/1/28/2107…

There's a broad range of R0 estimates — from 1.4 to 5.47 — being put forward. (R0 is how many other people one sick person is likely to infect on average in a group that’s susceptible to the disease.)

That's normal; it's early in outbreak & in best case, R0s not stable.👇2/8

But some of the leading epi modeling labs — @C_Althaus @maiamajumder @JonRead15 — are coming out with estimates that suggest a much narrower range:

2 to 3.8.

For context:

https://twitter.com/Vaccinologist/status/1220469109378502658?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1220469109378502658&ref_url=https%3A%2F%2Fwww.vox.com%2F2020%2F1%2F28%2F21079946%2Fchina-wuhan-virus-deaths-pandemic

. 3/8

These estimates are still imperfect, provisional, and likely to change in coming days.

But at the moment, they suggest the new coronavirus could be at least as contagious as seasonal flu and potentially more contagious than SARS... 4/8

Now, even a high R0 doesn't necessarily mean a disease will go pandemic, @maiamajumder warned: 5/8

We also don't have a clear picture of the case fatality rate — another essential concept in understanding how serious an outbreak can become. What's that?

It's the proportion of deaths a disease causes within a group of people who have the disease. 6/8

It'll be a while before we have good data on the numerator and denominator in the CFR equation — and early on, CFRs can seem higher than they turn out to be. Explanation 👇7/8

So it's still early days. And while there’s a great hunger for clarity about how bad the outbreak will become, frustratingly at this stage, researchers need time to work that out. 8/8

FIN