Covid-19: You can only predict with the data you have. Scary numbers in context

Like so many commenting on this Covid19 crisis - I'm no expert. I just connect the dots to try to understand - just as I do with anything else I experience.

So here's my guess on what the Government is up to:

1. They were always planning to put the vulnerable in a long period of isolation. The bet was that in isolation very few (comparatively) would succumb. They were expecting the 10s of thousands of deaths number they now hope to manage us towards.

2. Acting in this way early enough would allow the wider society to continue to function and - crucially - the NHS to cope.

They assumed that those requiring hospital beds would broadly be in that vulnerable group with limited exposure. But lots of younger folk need some care. They survive - but they need NHS resources. That's what the data shows from Lombardy - and that creates the crisis point for the NHS.

I think the tipping point moment for the Government was when they recognised (only this weekend) that there were likely to be up to half a million cases in the UK already - not the few thousand detected. In that scenario it is highly likely that those now being asked to isolate for months include large numbers who have already come into contact with the virus.

That could result in significantly higher numbers of deaths than an earlier invocation of isolation for the vulnerable would have caused.

If you take a (broadly) mid-point mortality rate between the Chinese and Italian experiences you end up with 100,000s of thousands dieing in the UK. This sounds scary big but remember, 550,000 people die in the UK every year and many of those this virus will be accountable for are substitutional rather than additional (ie folk who may well have died in the same 12 month period).

To provide some further context, if 100,000 people do die in the UK - that's one in 600. Alcohol or drugs kills 1 in 34 , heart disease 1 in 4. And the average American has a 1 in 77 chance of being killed by firearms.

Had we moved to isolate the vulnerable earlier, the period of social distancing for the rest of us that is now required could have been significantly shortened. But you can only predict with the data you have. And that 500,000-cases-in-the-uk guestimate is very new.

My guess is now that restrictions will only be lifted once the vulnerable are secured and the hospitalisation-rate among them calculated.

The Great Pause has begun.