Daily Status, October 7: Good numbers...though some hints of White House impacts
Daily Status, October 7
The COVID-19 data reported by the Virginia Department of health on October 7, 2020 (based on data collected on October 6th by 5 PM) shows that the commonwealth added 509 COVID-19 cases, which is one and 1/2 standard deviations below the 3-week average of 826 cases per day. Over the last seven days, Virginia reported 5420 cases, or 774 cases per day on which works out to 9.2 cases/100K people. This is down from 12 cases/100K several weeks ago, but above the 9 cases per 100K from 1 week ago. This suggests the decrease we are seeing for the last few weeks has has slowed. The trends over the last three weeks, though, do still show a decrease, with the case load decreasing at 1.5%/per day, 10.5% per week. Only 39 of the new cases were associated with colleges, mostly (32) from of those cases are from UVA, VT and JMU. It must be noted that the numbers at colleges are the lowest since the initial outbreak at Radford began about 50 days ago.
Regionally, all districts showing are flat to negative case growth. The testing numbers now show the percent positive to below the 5% metric over the last week (4.65%) 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 that would require funding.
On one other front, over the last week, we are once again below the metric of 10 cases per 100,000 to enter states like NY without quarantine -- we are at 9.7 cases per 100K, down from 12 or so a few weeks ago, but up from 9 one week ago. We remain able to travel to NY/NJ for at least one more week.
Outside of a few 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), almost all of the state is blue or clear, meaning less than a 10% chance of someone else in there being COVID-19 positive (still to high for me, but everyone has different standard or risk they are willing to accept).
In the spring, COVID-19 in Virginia was primarily a concern in the DC suburbs. Over a 3-4 weeks, in late may to early June, NOVA recovered, and for about a month, the disease was under control, to the point where the restrictions were eased. Unfortunately, in eastern VA/Hampton Roads, the easing of restrictions results in a surge in cases, which peaked around August 1 (and resulted in stricter restrictions in that area). Since then, the the exception of growth on college campus, the disease has been stable, except for the rural parts of the state, where safeguards are largely ignored. The trends are clearly visible in the figure below.
With this, we have completed the transition from COVID-19 being an urban disease to being a rural disease. 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. Newport News is also seeing a small increase which is possibly associated with a Donald Trump Rally 10 days ago.
NOVA: 0.977 -- GMU
Central VA: 0.984 -- VCU
Hampton Roads/Eastern VA: 0.955 -- W&M, CNU & ODU
SW VA: 0.975 -- VT & Radford
NW VA: 0.961 -- JMU & UVA
The state as a whole is is decreasing with Rt=0.978.
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, but are showing improvements as the college cases are getting somewhat under control -- or at least better than they were. Without the college cases, those regions would be closer to 9.0/100K.
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. Note that the nose-dive in the chart today is 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.
One trend not captured in these plot is the impact of a large (3000 person) political rally in Newport News on 9/25. Newport News was averaging about 10 cases a day. Then, 1 week after the rally, they had 20 cases for two days. That suggests that the Trump Rally may have been responsible for 20 extra cases of COVID-19. And then the next day was the super-spreader event at the Whitehouse.
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.
1) You can repost / share in the entirety by forwarding the link, 2) If you want share partial content, you must receive my permission – I need to make sure you understand what I am saying. If anyone sees this work being used without attribution, please let me know as soon as possible. I am willing to have an informed discussion / debate on my approach, but I want to make sure the proper context is captured.
Other Sites: John's Hopkins
Kids can pass covid to parents: Pediatric SARS-CoV-2: Clinical Presentation, Infectivity, and Immune Responses