Coronavirus updated thoughts - March 25th

It has long been postulated that the US is about 1 week behind Italy in terms of our dealings with the Coronavirus outbreak. While I have been watching the metrics closely related to the US situation, I've also been keeping my eye on Italy because of this view ahead.

Additionally, as I wrote about on my Facebook feed a few days ago, the US data on "new cases", which should be a leading indicator is completely untrustworthy and may be off by 10-100x. Many experts have published the same thing, but from a more virology and medical scientific view. I'm just looking at the data and a few basic facts that seem to be widely agreed to by these experts. As we are rapidly ramping up testing, everyone is starting to realize that the US may be the hardest hit country in the world purely by number of cases.

Here's a shorter version of what I wrote this past weekend:

In focusing on the US, it has become quite obvious that using the number of new cases or total cases is a mostly worthless metric. I'm still seeing stories and complaints among health care workers that not only can they not test unhealthy patients that meet all of the criteria, but also test results may take up to a week to come back.

One thing which I do believe to be accurate however is the "new deaths" or "total deaths". From studying the pattern in China and S.Korea I also have concluded that there's about a 2 week lag between case diagnoses and mortality.

An obvious conclusion then, is for there to have been 57 new deaths in the US on 3/19, that there would have to have been around 5700 new cases on 3/5 in the US. I'm using a 1% Mortality Rate for this math.

How many cases did the US report on 3/5? 63. Yes, it is quite likely that new cases data are off by a factor of 100x. This would make the US one of the hardest hit countries in the world, but still on a per capita basis be in the early stages of spread.

The other bit of math to use is the assumptions around virus spread. Experts are saying that the virus spread is doubling every 3 days. If we use "new deaths" as an indicator of how fast it's spreading, we do get that picture of exponential growth at some point in the process. However, we also get some encouragement:

Look at the chart titled "Predicting Spread". In the last 4 days we've seen the "4 day multiple" (which is calculated by dividing the "new deaths" of a given day by the "new deaths" of 4 days ago) plummet dramatically. Now remember, 2 weeks ago we hadn't started implementing crazy amounts of mandated social distancing. 4 day multiple is measuring "rate of spread" by the only accurate measurement we have.

It's only 4 days, so it may not indicate a trend or end up being statistically significant. However, any large trend or significant trend first starts small. And before this thing gets better, it has to stop getting worse.

Unfortunately, this 4-day trend did not turn into something. It represented a brief pause before the new deaths broke new records in the US. However, I'm also not surprised as we were doing almost nothing besides washing out hands 2 weeks ago to combat the spread.

For your record, we started implementing social distancing on 3/13 and the 15 day distancing period announced by President trump started on 3/16. Which means we are at least a week away from seeing the benefits of these countermeasures.

Let's take a look at Italy now in their new case view of things. New cases is never going to be 100% accurate, but Italy has been testing extensively for quite some time compared to us. Death rate patterns will trail new case data by up to 2 weeks.

While we have seen a 4 day trend get wiped away multiple times, I'm not sure I've seen a 6 day trend experience the same thing. 6 days is more significant. So what happened 2 weeks ago that may have led to this trend? https://en.wikipedia.org/wiki/2020_Italy_coronavirus_lockdown

2 weeks and 1 day ago was March 9th and it's the very day that they announced their major lock down efforts. Are we starting to see the benefit of that lock down show up in the numbers finally in Italy? Are we 1 week away from seeing similar benefits show up for the US?

Even if so, the death rate will continue to climb and be quite high over the next few weeks, even as cases slow down.