May 17, 2020


This part will be short, because nothing really stands out. Tomorrow, the U.S. will hit the 90,000 mark in deaths, and there’s no sign that we won’t reach 100,000 by next Sunday’s county report.


1) Cases: Last week, the trend line for Los Angeles County was upward; today the daily case rate has more or less plateaued. Some people look at this line and assume the plateau is over with, and the path downward is well underway. The data just don’t support that yet. The counties that are definitely on a downward path are San Francisco, Santa Clara and Sacramento. Riverside is on the beginning of a downward trend, but it’s still early to tell. San Diego’s trend was slightly upward last week, and it remains so today. Orange county and Ventura are on a pronounced upswing.

2) Fatalities: The sparkline charts on daily fatalities tell a similar story: Los Angeles, Riverside, and San Diego on a plateau. Orange, though increasing in daily cases, seems over the hump on fatalities. San Francisco and Santa Clara a lot better on both fronts. Ventura looked good, but then fatalities started climbing again. The case fatality rate (CFR) in LA continues to be the highest, at round 5.6%. Meanwhile, Kern’s is at 2%. I’m not positive what accounts for the difference. It could be that LA County has a much bigger population of densely populated areas with high rates of poverty and lack of access to medical care. Also, LA County has a huge percentage of “essential” workers, i.e. people who don’t have a choice about physical distancing. But I don’t know for sure.

3) Testing: San Francisco is definitely the leader, with 48k tests per million people, while Orange is on the bottom with half that amount. Only Santa Clara, San Francisco, San Diego, Orange, and LA counties make testing data available, so I have no idea where the rest of the counties are on this spectrum. The polynomial trend line for LA tests per week is interesting. There was a peak during the week of 4/26, and two successive weeks of decline since then. This is a bit strange since, at least in the city of LA, anyone can get a test who wants one. Some of the best results on the testing front are coming from San Diego county, where the weekly total has increased almost every single week.

4) Hospitalizations: I’m including two charts on hospitalizations, not because I’m sure how to interpret them, but more in hopes that someone out there can explain some of the glaring differences between counties. For example, why is LA County’s hospitalizations per 1M almost twice that of San Diego’s and everyone else’s? I’d be tempted to say it’s a function of income, but then Kern, which has the lowest average family income of all these counties, also has one of the lowest hospitalization rates.

CONCLUSION: The counties don’t tell a uniform story. Some counties like San Francisco issued stay-home orders even before the state did. The mayor’s quick action there looks like it paid off. When a virus has an R0 of between 2 and 3, just 2 or 3 days can make the difference between an outbreak that is relatively quickly contained, vs. one that lingers on and on at a high level. At the same time, we can’t forget that the economics of LA County and SF County are vastly different: LA has an average family income of $68,000; SF has an average family income of $137,760.

While there are a couple of counties that look like they might open up cautiously — San Francisco, Santa Clara — the rest will probably need some more time. We’ll see how things have progressed next Sunday.

Stay well, everyone!

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