What the Data Shows, viral and cyclonic (13 May 2020)

Lots of COVID charts today, but sadly no math 🙁 .  First the tropics: The data shows that Typhoon Vongfong will sweep through the Northern Philippines over the next few days.  The bad news is that it is strengthening faster than anticipated and will be much stronger than forecast yesterday, but the good news is the track has shifted so that the brunt of the storm will stay offshore.  Here’s the map:

On the pandemic front, nothing much has changed.  While testing has increased, it isn’t really changing the picture much, which seems to indicate the virus is spreading about as fast as the testing – fortunately (or not depending on your perspective), neither very fast.  Yes, the fraction of people tested is increasing …

BUT, the fraction of those tested showing up positive, and the fraction of people tested who are in the hospital, remains fairly constant, especially the ratio of hospitalized to tested, which is an amazingly flat rate for the areas we have data:

What that means is for almost the last two months, pretty consistently about 1 in 5 people tested are showing up positive and 1 in 5 of them (4% of the population tested) end up in the hospital.  You would expect that number to decrease over time as testing increases if the number of people with the virus is decreasing.  So again it seems that people are catching the virus about as fast as we are able to test for it … as for mortality, it seems like between 4 and 6% of people who are testing positive and are hospitalized ultimately end up dead (noting Michigan is an outlier for a number of reasons):

So, for the whole population (everybody, no testing assumptions), the mortality rate seems to be converging to a range between 1 per 10,000 in places like Germany/Denmark, between 2 and 3 for Russia/Canada, 4 per 10k for Sweden/Netherlands, and to between 5 and 7 per 10,000 in places like Italy/Spain/UK. In the US, it’s about 1 per 10,000 overall, HOWEVER in the population centers like NY, NJ, Lombardy Italy, etc., where there was an active outbreak it is converging to between 10 and 12 per 10,000, but contrast with California, Washington, rural areas at less than 0.5/10k. Georgia is right at the national value at the moment.  So who you are (older, immune system problems) and where you live (population density) changes your risk by a factor 100 (!) or more.

The results of the grand experiment by Georgia (and the other states who are “opening up”) are not yet in.  That should start to show up over the next week or so.  As always, keep in mind how slow moving this is.  In hurricanes we think in terms of days, but for pandemic, it is weeks.  It takes about a week to ten days for changes in policy and behavior to even begin to show up in the data – and in hospitalization and mortality, two to four weeks.  For Georgia, we might see the positive rate change, but probably the first reliable metric we will see a change in (or not) are hospitalized patients.  Here is the raw data for Georgia.  Don’t be alarmed by either the flat bit or the uptick over the last few days – as you can see, this “curve” is noisy (and obviously to an extent bogus, since we had COVID patients in the hospital in mid-March, yet the reports say “zero”).  But it’s what we have …

So … nothing much has changed.  Please continue to be patient and very careful – use good hygiene, limit contact with others to the extent practical, masks when in situations where you can’t.  For vulnerable populations (over 65, health problems, etc) be extra careful and shelter-in-place should continue be the rule.  And those who care for them (literally and emotionally) please be super careful you don’t infect them.  We need to find a balance, since this isn’t going to end any time soon.

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