Daily Status, October 12: The cases in Virginia are clearly starting to increase again.
Daily Status, October 12
The COVID-19 data reported by the Virginia Department of health on October 12, 2020 (based on data collected on October 11h by 5 PM) shows that the commonwealth added 854 cases of COVID-19, which is in line with the three week average of 866 cases, but well above the 606 expected number when corrected for the day of the week (Mondays are typically below the average by 30%). I am now confident that the downward trend for September was either a fluke or is over. Viewed over the last seven days, Virginia reported 7013 cases, or 1002 cases per day on which works out to 12.0 cases/100K people. This is consistent with 12 cases/100K several weeks ago, but well above the 9 cases per 100K from late September week ago. It is worth noting that there was a dip in hospitalizations that coincided with the September dip, leading me to believe it was real. Furthermore, if we subtract the effect of the college outbreaks, there was a constant decrease from just before August 1 to Sept 25. By October 3, there was a measurable increase. The new increasing trend is real.
The trends over the last three weeks, now are showing a slow increase, at 1.5%/per day or 11% per week. I am unable to estimate the cases at colleges as that requires the zip-code data which is not available for 10/10.
By combining our current regional trends with the typical reporting for the day of the week, I expect 915 cases tomorrow (Tuesday) with a 90% chance of the numbers falling between 619 - 1362 cases. If tomorrow's numbers differer from that, we are having a very rare event.
Regionally, all districts showing are flat to positive case growth. The testing numbers now show the percent positive to below the 5% metric over the last week (4.56%) that is often used to indicate sufficient testing (e.g., is is safe to reopen schools). Virginia is testing about 2.8% of the population every two weeks, which is about 1/4th the number of tests desired for random sampling, but most of the Commonwealth's testing is driven by medical needs and not surveillance. Surveillance would ideally test at least 5% of the population per week but the testing is somewhat invasive..
On one other front, over the last week, we well above 10 cases per 100,000 to enter states like NY without quarantine -- we are at 12.0 cases per 100K. My suspicion is our ability to travel to NY/NJ was the result of flawed reporting, and we will be unable to travel to NY the next time they update the rate.
Outside of a multiple smaller cities/towns, the state is doing better than it has since the Hampton Roads surge except we are seeing more localized outbreaks; the hot spots are isolated and probably associated with facility outbreaks. Also, looking at the chance of being exposed in a group of 50 (e.g, eating at a restaurant), while almost all of the state is blue or clear,, the teal to yellow regions (dangerous) are increasing.
But, looking at the weekly numbers, it appears that the rural areas, whose caseloads were already increasing, surged with the the influx of a carefree demographic (college students). I think we area so seeing some impact of the White House outbreak, as many employees live in northern VA. This is mostly showing up in the Upper Middle Class suburbs.
Looking at the weekly case count, we see that the case numbers are more in line where we were at the beginning of September. I am unsure if the September low was the result of fewer cases or the result of poor reporting.
NOVA: 1.020 -- GMU
Central VA: 1.010 -- VCU
Hampton Roads/Eastern VA: 0.975-- W&M, CNU & ODU
SW VA: 1.000-- VT & Radford
NW VA: 0.995 -- JMU & UVA
The state as a whole is is increasing with Rt=1.015
The following table shows the number per 100k for each region. Again, NOVA and Eastern VA are doing the best, and the mountainous regions in NW & SW continue having more cases. The concerning aspect is in all regions, the numbers for last week are significantly higher than the prior 3 weeks.
The following charts are for the 5 regions. in the chart that shows all regions, The individual line charts show the unfiltered data per day, coupled with the trend lines. The trend lines show the different periods of growth. Early in the pandemic, the different parts of Virginia were functioning largely independently, with NOVA mimicking the northern states, and Hampton Roads mimicking the southern states. But, since September 1, the regions have trended with each other. Starting in late Sept., NoVA and SWVA diverged from the rest of the state. The increase in NoVA amounts to a total of about 750 extra cases, which may be too many to attribute to the 9/26 White House event.
Note that the effects at both ends of the chart are probably an artifact of the 7-day polynomial filtering I use. The filter is called a Savitzky-Golay filter, and basically is a moving window polynomial filter. At the edge (first and last days of the time series), the filter will over compensate for the trend.
Growth rate (%/day)
Last 10 days
% that had COVID***
* estimated from the number of cases in the zip codes associated with the university removing the pre-student arrival case rate
Large Scale Community Spread:
- People can test negative and still spread the disease.
- Even if everyone who interacts with you is tested immediately prior to the interaction, you can still get sick (see 1).
- If you have an event with hundreds of people, there is potential for it to be a super-spreader event, even if you test everyone at the event.
- If you do this frequently enough, you will get unlucky.
- A non-spaced, but outside event is still dangerous.
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Other Sites: John's Hopkins
Kids can pass covid to parents: Pediatric SARS-CoV-2: Clinical Presentation, Infectivity, and Immune Responses