I will try to graph this later. But a quick point I wanted to flag. There is some possible – I stress possible, not at all certain – that the horrific outbreak in Italy is starting to slow down. Over the last three days the number of new infections have tracked down from 6,557 > 5,660 > 4,789. The fatality numbers have tracked 794 > 651 > 601. If the 21st was the peak day, that would be 13 days after the lockdown in Lombardy on March 8th (followed by a national lockdown a day later.)
This is notable because the number days between the lockdown of Wuhan and the peak day of new infections in China was 12 days.
This is at least broadly consistent with what we know of the epidemiology – up to 14 day incubation period, 5 or 6 days as the median number of days before people become sick and then another week before those who are on a severe course to become critically ill.
It is course important to remember that this emphatically does not mean things are getting better in Italy. If that pattern holds it will mean they are getting worse at a slower rate. Still, these inflection points are critical to understanding what is happening. I would also stress that the numbers from Italy have bounced around somewhat over the last week, appearing to stabilize before going up again. We need to see more days of this pattern to know it’s a real shift.
Where this leaves the US is much less clear. The lockdowns in the US have been much more incremental. And people have been circulating more or less as usual in most of the country until the last few days.