So we are in the middle of a pandemic. Or rather in the beginning according to some projections. And every new day we spend indoors working from home with two little kids, makes me a little more motivated to follow of trends of the new cases data in our area. I hope this will help you stay informed.
Silicon valley traditionally included only South Bay, but nowadays it really refers to everything between San Francisco to San Jose and spans three different counties – Santa Clara, the largest county, San Mateo and San Francisco. Longitudinal data for all of these counties is not easily available because the official websites report either all the numbers or the fatalities numbers only for the current day. To trace our trajectory, I collect daily data from the official websites, corroborate it with other news outlets and update the cases chart.
Updated on 04/20 [note San Mateo data reports lag one day, so all data here lags one day] This chart is showing the cases in the three counties. The number of cases went up today by 98 cases with a total of 4039. The growth in the last week has been fairly stable, between 100 and 200, per day. Two new deaths were reported. The count is at 125 deaths (3% mortality rate, although see the discussion of new research findings below).
Two new fatalities were reported in Santa Clara county with a total of 77. With 1903 total cases, it makes for a 4% death rate. Good news is that the death growth in Santa Clara continues to be linear – the dashed grey curve on the graph is a linear fit with a slope of 2, which means 2 new fatalities per day on average. The line for the valley is closer to 4 fatalities per day. According to new data from the county, San Jose accounts for ~70% of the COVID-19 cases in Santa Clara county.
New research, randomly testing a sample of the population for presence of COVID-19 antibodies, from Stanford found that the real number of cases in early April should be between 48,000 and 81,000, 50-85-fold more than the number of confirmed cases (~1K in the first week of April). It that is the case, the true mortality rate in our county is closer to 0.1%.
More good news come from the new data on hospitalizations. It seems like what we are doing is working. The hospitals are not overrun. Currently about 1/3 of the ICU beds in Santa Clara county are available (99 beds) and 77% of the ventilators are not in use and available (609 ventilators).
On March 26th, the San Jose Deputy City Manager Kip Harkness said that “Even in the best-case scenario, we were looking at the order — in the next 12 weeks — of 2,000 potential deaths directly from COVID-19” in Santa Clara county. The article reported that “officials have not explained publicly how they devised those estimates” . At the time, I investigated this using the available data I’ve been tracking. I projected a polynomial growth curve, that fits the cases data the best, 12 weeks from March 26th and got 53.5K cases. The mortality rate in the last weeks has been dancing around 4%. If we apply this rate to the number of cases, we, sadly, get 2.1K.
However, the death growth in Santa Clara county has been linear with a slope of 2. So if we project this curve to June, we only get ~150 fatalities. Much better than what we expected based on the data in March.