Sept 23: I suspect there was a data reporting issues...Numbers look too good.


Daily Status, Sept. 23

Reminder:  any sections that are unchanged since yesterday are grayed out.  

Situational Awareness

Some days, you look at the numbers, and shake your head.  Today, the number of new cases is low -- very low.  Depending on assumptions of the distribution, we are 2 (normal) to 2.5 (log-normal) 𝛔 below the mean, meaning this should happen about 2.5 to about 1% of the time randomly.  Alternatively, either something went wrong in the the data collection or things are really improving (statistics changing).  My best guess is a data collection issues (computer issue?).  And in a day or two we will have a huge number of cases: 2-3 𝛔 above the mean.  Because of this, I do not plan to spend much time interpreting the numbers;  I will document them, but any text will be unchanged.  Today had the fewest cases reported since the July 4 weekend.

Across the commonwealth of Virginia, there were 580 today reported new cases of COVID-19, which is more than 2 𝛔 below the 3 week average of 975 cases.  Overall, cases are decreasing  for the last three week at 1.3%/day. Surprisingly, there were very few new cases at colleges:  no school had more than 20 cases;  total was 67 cases in college towns, which is the third straight day with less than 100 cases.  But, these could be because the health centers are closed on Sundays.  Regionally, all districts showing are flat to negative case growth. The testing numbers across the state remain ok, with between between 4 and 5% positive, which, if Virginia can maintain, will be significant, as 5% is often listed as a target number.

On the college front, most of the colleges updated the dashboard on Monday or today. Most seem to be trending in the right direction (UVA possibly being the exception).  VT looks like it may have turned a corner, Radford has.  JMU is still recovering.

Outside of college towns and a few smaller cities/towns, the state is doing well.


We have completed the tradition from COVID-19 being an urban disease to being a rural disease.  The urban centers of NOVA and Hampton Roads are showing the lowest infection rates whereas the highest rates are in the SW, and NW parts of the state which are mostly rural.

Regional growth rates are (in fraction per day) continue to to show improvement.

NOVA: .990 -- GMU

Central VA: .990--  VCU

Hampton Roads/Eastern VA:  0.976-- W&M, CNU & ODU

SW VA:  0.961- VT & Radford

NW VA:  0.967- 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 in those regions 35% of the cases were from the colleges.

Daily Cases/100,000 
(corrected for testing)


Last month

Last week
















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  For the last month or so, we note that NOVA have been flat at around 300 cases per day.  Hampton Roads (Eastern) dropped from about 800 to under 200.  Since labor day, when the Governor relaxes restrictions on that region, the cases have started to rebound.  The rest of the state shown small declines.  Again, SW VA, even with the lower population, has roughly the same number of cases than any other region. 

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. Earlier in the week, we have what appears to have been a random blip, where it appeared the caseload was dropping; we have since returned to our 200-300 case per day baseline. Note that hospitalizations and deaths remain much lower than the peak in May.

Currently, all jurisdictions are flat to slightly declining.

Fairfax Co.: 0.995
Arlington Co.: 0.991
City of Alexandria: 0.978
Prince William Co.: 0.992
Loudoun Co.: 0.981

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 about 1, and our rate of cases is about 7/100,000 per day.  Ideally, we would be 0, but 7 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, there trend has gone from 1% per day to -5% per day Now, Arlington has the fewest cases 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.  It will be an interesting experiment.

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.  One trend that is clear:  a month ago regions north of US50/I55 were had lower COVID-19 rates than those south of the highways.  That is no longer the case. . Also the new "yellow zone" in the SE part of the map is considered to be outside of Northern VA and in Caroline County.  It may be related to an outbreak at nursing facility.

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, all of Northern VA is showing less than 10/100,000 cases.    Vienna, appears to be stabilizing, or perhaps has had a 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.


Last month

Last week

Growth rate (%/day)

Fairfax Co









So. Alexandria








Annandale/Fall Church









No. Arlington




So. Arlington




Alexandria City




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: 

We see the bump in the age distribution from the JMU students returning home There are about about 150 cases more than I would expect in the last two days for teens.  Since there are probably about 1500 JMU freshman from northern VA (that is a guess), 150 cases is about right.  We are now back to the baseline number for that age group (the polynomial soothing I apply makes it look like there are fewer cases). The concern is that the JMU students will infect their families, and we are seeing an uptick in cases in the Middle Aged populations, up about 20 cases a day.  

Note, I will talk about the age distribution in college communities under "college communities"


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.


% Positive

VDH Cases*

Estimates Cases Tot/LW **

Dashboard Cases

% of population infected ***

Va Tech




























































* 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:


I would consider moving Radford to the "Watch list" once the percent positive drops below 10%.  But, with more than 20% of COVID tests being positive, I can not move it.  Note that this is a significant improvement from two weeks ago when 80-90% were positive.  By all metrics, though, the outbreak seems to have peaked.  It is not clear 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. 

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 27% 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.
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; anecdotally, I have heard stories of students not getting tested because they do not want to quarantine.    The most concerning aspect of Va Tech is 20% of the tests are coming back positive.  That suggests that either they are rationing tests, or they are undercounting.  Either way, I estimate indicate more than 5%, and probably 10% of the student body is positive.  Short of a two week pause, I am not sure how Tech will contain the spread. It is worth noting that the outbreak has also impacted the VT football team; they are having to halt practice and delay the start of the season. Virginia Tech tested only on-campus students.  
With the students return, there has been a marked increase in cases. I was ready to say UVA has things under control, but they had a 25% jump in cases over the last few days.  This is either a random bad day or the start of a trend.  Either way, I will continue to assert there is community spread, and I will keep a close eye on it.  UVA tested all students prior to arrival on campus.

Watch List: 

Other schools:

William & Mary -- so far so good -- No evidence of community spread.  There are now cases on campus.  W&M says less than 10 cases, but 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. 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. 

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; that will probably result in multiple deaths in the community.  This is the concern.


The situation in Vienna is not as good as it had been.  We had been lowest infection rates in the Fairfax co, and in the state.  Now, we are above the mean for the county.  I do not know the cause of the increase in cases; today, when out in the morning, outside waiting for coffee, 95% of the people were wearing masks.  That is good.  But, I am hearing enough people that are frustrated with the way things are. There are People expanding their bubble, taking more risks.  That leads to more cases.  Vienna can do better.


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.


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.

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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