Daily Status, Sept. 25: are we turning a corner? I hope so.
Daily Status, Sept. 25
Reminder: any sections that are unchanged since yesterday are grayed out.
Situational Awareness
I am happy to report things are again pretty good; today showed the lowest number of cases on a Friday since July 4th Weekend.
Today, Virginia has 941 newly diagnoses COVID cases. One thing to understand is the number of cases is usually higher on Thursday, Friday and Saturdays, and lower on Sunday, Monday and Tuesday. If we look at 7 day numbers, we have averaged 818 cases (9.8/100K), which is 2.4 standard deviations below the mean weekly number for the last 10 weeks. This should happen, randomly less than 1% of the time, which means there is statistical significance to the weekly numbers. Overall, cases are decreasing for the last three week at 1.3%/day, or 8% a week. While numbers at colleges are up, most of it is at three schools: UVA, VT and JMU. few weeks ago three individual colleges (Radford, VT and JMU) were near or above 100 cases. The only school of concern is UVA, which just enacted restrictions to bring the numbers down.
Regionally, all districts showing are flat to negative case growth. The testing numbers are now closer to 4%, well below the 5% ismetric that is often used to indicate sufficient testing (e.g., is is safe to reopen schools).. On one other front, over the last week, we are very close to the metric of 10 cases per 100,000 to enter states like NY without quarantine -- we are at 9.8 down from 12 or so a week ago. If the numbers do not increase, we should be off NY's quarantine list soon.
Outside of afew smaller cities/towns, the state is doing well.
Regions:
Regional growth rates are (in fraction per day) continue to to show improvement.
NOVA: .991 -- GMU
Central VA: .998 -- VCU
Hampton Roads/Eastern VA: 0.974 -- W&M, CNU & ODU
SW VA: 0.959 -- VT & Radford
NW VA: 0.960 -- JMU & UVA
The state as a whole is is decreasing with Rt=0.987
The following table shows the number per 100k for each region. Again, NOVA and Eastern VA are doing the best, and NW & SW are doing the worst, but are showing improvements as the college cases are getting somewhat under control -- or at least better than they were.
Daily Cases/100,000
(corrected for testing)
Region | Last month | Last week |
NOVA | 9.1 | 7.6 |
Eastern | 9.9 | 8.3 |
Central | 12.4 | 11.0 |
NW | 13.0 | 14.2 |
SW | 17.4 | 13.8 |
In the following charts, I modified them slightly, by including the growth rates in the "action labels".
The following charts are for the 5 regions. in the chart that shows all regions, the drop at the end is a processing artifact (the filter I use can overstate the end points; it is decent but not as steep of a drop as indicated by the chart). The individual line charts show the actual data.
Local/Northern VA:
In the trends of case, we can either describe it as slow growth since late June, or flat since early august. Both equally describe the data. But, for the last week, we are just below 200 cases a day.
Currently, all jurisdictions are flat to slightly declining.
Fairfax Co.: 0.996
Arlington Co.: 0.994
City of Alexandria: 0.995
Prince William Co.: 0.990
Loudoun Co.: 0.984
The growth rate is defined as Rt, or the growth time constant. Simply, todays number are approximately the growth rate times yesterday's numbers. This is the exponential time constant. Fortunately, the time constants are below 1 and our rate of cases is about 6/100,000 per day. Ideally, we would be 0, but 6 is much better than our peak in which was around 30/100000K.
About 4 weeks ago Arlington began enforcing social distancing guidelines -- or at least threatened to. Since then, Arlington went from a high jurisdiction to the lowest caseload per capita whereas Alexandria and PW have the most. The enhanced enforcement (or threat of enforcement) worked, but on 9/16, the Arlington County Board of Supervisors voted to let the restrictions expire at the end of the month.
What is most noteworthy of the NOVA Zip code map is the the overall lack of contrast. With the exception of near zero population localities, every part is doing about the same. There are small scale variations, but the relationships seem to be more related to locations with more shared living arrangements than anything else.
Every part of Northern Virginia is down last week compared with the last month, except for Vienna. The good news is, in the last week, almost all of of Northern VA is showing less than 10/100,000 cases. Vienna, has recovered from a post-labor day mini-peak, and is the case load is now probably reverting to the prior status. Interesting in the Zip Code map above, 22180 has dropped to a darker blue.
Region | Last month | Last week | Growth rate (%/day) |
Fairfax Co | |||
Vienna | 7.0 | 5.2 | 4.6 |
McLean | 5.5 | 5.6 | 2.1 |
So. Alexandria | 9.8 | 8.5 | 1.4 |
Reston/Herndon | 8.5 | 8.7 | 1.9 |
Annandale/Fall Church | 10.9 | 8.9 | 0.8 |
Fairfax | 7.2 | 6.9 | -0.8 |
Arlington/Alexandria | |||
No. Arlington | 6.2 | 5.8 | -1.4 |
So. Arlington | 10.6 | 9.1 | 3.5 |
Alexandria City | 11.9 | 12.3 | |
During most of the last 2 months, Vienna and McLean tracked each other, as did Reston and Fairfax. Except, for labor day to last Friday, where Vienna increased its case load. Now, though, it appears Vienna and McLean are again tracking each other.
Age Distribution:
As expected, there was an increase in cases among Middle Ages (and young adults) delayed from when the JMU students returned home. There are about about 150 cases from the JMU students. We are now back to the baseline number for that age group. The JMU students infected their parents, resulting in an increase of The concern is that the JMU students will infect their families, and we saw an uptick in the middle aged population, which has since recovered; about 50-100 extra people were infected, which was less than I expected.
Note, I will talk about the age distribution in college communities under "college communities"
College
My process combines the VA Department of Health data and what is reported by the colleges. The report is as of 12:20 ET. I need to point out that the VDH cases may include cases not affiliated with the university as I am using geographic surveillance. It is also worth noting that all assume that students feeling ill are going to health service; I have heard anecdotal reports of people not doing that because they did not want to quarantine. The colleges usually update the dashboards after this post, or on Monday/Tuesdays. Except for Radford, all weekly updates are complete at this time. And the numbers are encouraging (except for UVA).
Note: I have also added estimated cases within the last week.
RED means there is clear evidence for community spread
YELLOW means there may be community spread; still ambiguous
GREEN means no evidence of community spread
BLACK means they went online.
College | % Positive | VDH Cases* | Estimates Cases Tot/LW ** | Dashboard Cases | % of population infected *** |
Va Tech | 9.3 | 1243 | 4240/424 | 925 | 12.4 |
GMU | 4.3 | 3 | 17/6 | 43 | 0.0 |
UVA | 10.4 | 470 | 1167/270 | 552 | 4.9 |
ODU | 4.6 | 40 | 72/3 | 59 | |
JMU | 21.8 | 1450 | 6551/637 | 30.9 | |
CNU | 5.5 | 5 | 28/0 | 14****** | 0.6 |
UMW | 3.8 | 1 | 6/0 | 10 | 0.1 |
Radford | 10.0 | 558 | 2649/26 | 409***** | 33.4 |
VCU | 3.4 | 155 | 313/0 | 239 | 1.0 |
W&M | 2.1 | 0 | 0 | 10 | 0 |
* estimated from the number of cases in the zip codes associated with the university removing the pre-student arrival case rate
** estimated number of cases is an attempt to normalize for testing limitations. Specifically, I assume at 5% positive, 100% of the cases would be caught. so I normalize it to that value. If the % positive is very high (>40%) I am likely overestimating the numbers.
*** Dashboard cases are only counted if I can find the dashboard. In some cases, it is difficult to distinguish positive tests from cases (1 case may have multiple positive tests; that is mostly at VT). I include active cases if reported, otherwise, I use total cases.
****% population uses the total reported number of students rather than just those on campus; it may be off when the percent positive is above >40%.
***** Old data, not updated for today.
****** Active cases, not total cases
Large Scale Community Spread:
JMU is online. JMU has been fairly transparent with the situation, but could not get ahead of it. At this point, it is mitigation. Harrisonburg is still running 22% positive. They sent the healthy students home, and are allowing the positive to stay on campus, which is critical for society as a whole. It is worth noting that sending the on-campus students home seems to correlate with an increase in cases in that age group in Northern VA. There are now multiple hospitalizations in Harrisonburg that are of the age group expected for College students. JMU did not require testing prior to arrival on campus. JMU plans to reintroduce on-campus activities soon -- this time with about 10x the quarantine space and a plan for prevalence testing. Note that over the last two months, JMU students resulted in about 85% Harrisonburg's COVID-19 cases.
We have seen the prevalence of the virus in Blacksburg increase with the return of the students. Each day, there are 30 and 100 new cases validated. There could be more, but some people are just assuming they have COVID 19.Virginia Tech tested only on-campus students. In the last 2 months, VT student cases, as reported in the dashboard, has accounted for 66% of all of Blacksburg cases. But -- VT is only reported the student health center results,
With the students return, there has been a marked increase in cases. Week over week, UVA has been increasing by 25% in the case load. In the last two months, 76% of the case load in Charlottesville.
Watch List:
RADFORD
Radford was moved to the watch list, as there percent positive has improved. While it is not how many students at Radford contracted COVID-19. It would not surprise me to see enough that the community, when isolated effectively has herd immunity (meaning over 60-80% contracted COVID-19). The only way to know would be antibody studies. Hopefully, VDH will look into that. But, currently, it seems that Radford has a manageable number of cases. While only 57% of the cases in the last two months are attributed to students, there were so few cases prior to the students return, this means either the dashboard is undercounting, or there were a lot of non-students infected by students.
Other schools:
William & Mary -- so far so good -- No evidence of community spread. There are now a few cases on campus. W&M says less than 10 cases, but a week ago they also are reporting .15% positive in the last week when they tested 6000 students. That suggests 3-7 students on campus are positive, which is consistent with the state numbers for Williamsburg. That number has fluctuated a bit, but the Williamsburg numbers have remained low. It is worth noting that pre-arrival testing has identified 20 cases, which were not allowed on campus. W&M tested all students prior to arrival in town. Williamsburg is a case where the town/tourists are a bigger threat to the college, than the college is to the town. Over the last two months, only 16% of the cases were from W&M students, but the students are 40% of the town population.
VCU seems to have the virus under control -- They have beaten back an outbreak, the % positive is good, and there are few new cases. It was promoted from RED to YELLOW. and now Green. The numbers have shown no significant increase in the last several days; quarantine and isolation space is becoming more prevalent. Being in an urban setting the zip-code and regional surveillance that works well at some of the other schools is not particularly helpful here. So, I have to rely on the dashboard.
CNU -- Students have been back upwards 1 month. A few cases. Under control.
ODU -- Nothing noteworthy. My concern with ODU is they did not test the students, so there may be asymptomatic/presymptomatic spreaders on campus (see JMU). Yesterday, they updated the dashboard to show 59 cases on campus, which is about what I would expect based on non-tested students. But the dashboard has not been updated since Sunday. They update it once per week. We will see if they infected other students.
UMW -- Nothing noteworthy. A few cases but they just returned. I am concerned because they did not test all students.
GMU -- Nothing noteworthy. GMU tested all students.
College Communities:
When I started talking about communities, the focus was on the safety for incoming students. Unfortunately, that concept as changed. Now, we are seeing the colleges impacting the surrounding communities. If we look at the age distribution of cases in the communities of JMU, Radford and VT (New River, and Central Shenandoah health districts), we see that, starting about 2 week sago, number of cases for non-college age citizens is increasing -- about two weeks behind the college age curve. This suggests the disease is infecting the general population. So far, it looks like about an extra 100 seniors were infected; thathas resulted in a few extra deaths. This is the concern.
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Commentary:
Nothing to say
Attribution:
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.
Links:
Source data is from the Virginia Dept of Health COVID Site
Why I did this: About the blog
I have thoughts on the spread in college communities which can be seen here. This is the same link at the top of the write-up.
Other Sites: John's Hopkins
Kids can pass covid to parents: Pediatric SARS-CoV-2: Clinical Presentation, Infectivity, and Immune Responses
A fun video showing masks work, guy style:
How to wear a mask.
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Politics: Some lie.
Donald Trump yesterday said that without blue states, the death rate would be much better. He needs to stop using alternate facts. Red and blue are defined by who the state voted for in 2016. 47% of the deaths come from red states, which is about his percent of the popular vote. But, more importantly, after June first, when states could use science to mitigate the virus, 65% of the deaths are from red states. Facts matter.
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