Daily Status, August 19

Daily Status, August 19:


I made a few changes to figures.  

The figure that compared, NOVA to Hampton Roads/Eastern VA and Rest of VA now shows the 5 regions (and the data are now smoothed).

Also, the Vienna bar chart has been changed to a line plot and I added other parts of Fairfax County to the plot (e.g., RESTON/HERNDON, Fairfax, etc). My readership is increasing beyond Vienna...

Summary/Situational Awareness

Today, across the commonwealth, there were 737 new cases.  Overall, this is low side of recent data but remains 1 standard deviation of the three week mean.  None the less, we have five straight days where we are below the mean; the trend is approaching significance.  Regionally, Northern VA's slow increase continues.  With the exception of NW Virginia, the rest of of the state is trending down -- with the leader in the decrease being Hampton Roads/Eastern VA.  It is worth noting that the areas seen growth have a much lower prevalence of the virus, and and much better testing statistics.    The testing numbers across the state remain ok, but not great.

Overall, though in the state, North of I64 is doing better than south of I64, both in testing, number positive, and growth.  The brighter yellow regions are mostly south of I64, with the exception being the previously hard-hit areas around VA Beach and Norfolk.  The most problematic areas are some of the smaller cities.

There is an interesting experiment going on in Blacksburg:  Virginia Tech is testing all students upon arrival at campus, and those results are being attributed to Blacksburg.  That means we can get realistic numbers on the % infected. I am aware of other schools requiring testing, but most of those are prior to arriving on campus.  At this time, I am seeing the surge in testing, but no evidence of additional cases.  This means the background caseload is low, probably on the order of 0.1% or less (at least among those students that have returned to date).  It also means that the increased testing is not the cause for the increased caseloads. 


While the statewide numbers are decreasing, different patterns emerge regionally.  At different points in the pandemic, different parts of the state have had different disease prevalence (by as much as a factor of 10), currently all regions are doing about the same, with the week-over-week numbers decreasing throughout the state, though the three week trend line shows growth in Northern VA and NW VA.  The discrepancy may be the result of a data glitch which resulted in a reporting surge on August 7.  Overall, the regions are doing ok.  We need to be cautious throughout the state. Yesterday, the sky was not falling and today, we are not doing great.  But, as locations go, much of Virginia is improving, no overall region is particularly concerning.


The three week growth rates are (in fraction per day)

NOVA: 1.015

Central VA: 0.989

Hampton Roads/Eastern VA:  0.958  

SW VA: 0.996

NW VA:  1.036


The state as a whole down 0.5%, being driven by Hampton Roads (down 4.5%).  The reason why VA is improving even though most of the geographic regions are increasing because the largest number of cases are where the case load is dropping.

The following charts are for the 5 regions/trends.  To me, what is most fascinating is each part, even though we are mostly part of the same guidelines, 

Local/Northern VA:

The overall trend in Northern Virginia indicates, that after correcting, are case load has dropped by more than a factor of 10x since our early may peak.  We now are averaging about 200 new confirmed cases a day, down from about 3000 cases per day at the peak (because of the availability of testing, 40% of the tests were positive in northern VA, indicating that only 1 in 8 cases were confirmed).  Hospitalizations and deaths are also down.

Still, now, Northern VA is showing the amoung highest growth rate in the commonwealth.  By county, it is:

Fairfax Co.: 1.037
Arlington Co.: 1.016
City of Alexandria: 1.021
Prince William Co.: 1.004
Loudoun Co.: 1.019

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, while the numbers are increasing locally, they are low enough that drastic steps are not really required to stop the increase.

Again, though, while we have positive growth, the absolute numbers are low. 

If we look at the current status by zip code, we see that most areas are doing ok, though along the I95 corridor and US1 is doing worse.  Also, in general, for Fairfax and Arlington County, North of US50/I66 is doing better than south of I66/US50.

I am transition from a focus on Vienna, to looking at the overall region for local reporting.  To date,  have grouped six sets of zip codes.  I am missing Centerville/Chantilly/Clifton and the southern parts of the county.  

In general, we see the similar overall trends, but the absolute values offset my as much as 3x (this is a log plot).  Currently, the lowest numbers are in Vienna and McLean whereas the highest numbers are in Annandale and Alexandria and south.   My suspicious in the variation is the result of household income:  the wealthier parts of the county can afford to be more careful.

Elsewhere in Northern VA, Herndon/Sterling /Dulles is warm, as is the I95 corridor, and an area just north east of Warrenton.

Age Distribution:

The age distribution of cases shows growth (RT>1) among all age groups, but the working age people (young adults & middle age) are higher than younger and older groups.  And once again, the Teens and Tweens are showing the slowest growth rate (practically flat).  Once again, the teen bubble's social isolation from anyone not a teen is working for them.  It proves if one only associate with non-infected individuals, then the risk is low.  However, based on observed behaviors among that age group, if the disease expands at all, then there will be a problem.


As colleges start to reopen, there will be an interesting data experiment:  with large cohorts smaller communities, the impact of the colleges on the numbers should be apparent.  My plan for this is to track the colleges by zipcodes, particularly those where I can isolate the students or the students make up a majority of the population.  For example Blacksburg and Virginia Tech.  

I would like to crowd source zipcode information.  I am only familiar with Tech and William and Mary.  My guess is all of the larger VA schools that do not cater to commuter students (that is the students concentrate in one area) will show trends.  We may also learn a lot about the college cultures based on the response.  I would like to include JMU and UVA at minimum.  If we can isolate VCU, ODU, CNU, and UMW students relative to the surrounding communities, then  I can include those schools.  With the number of readers of this update, I am assuming that you can help me.  Please, if you know the relevant ZIPCodes for a Virginia college, please forward them to me.  So far, there are no case upticks in either Williamsburg or Blacksburg since students returned

Overall, I think we can feel confident sending our kids to college (assuming they are not stupid).  So far, the numbers for incoming students at Tech have been low – which is good.  I talked about that in my introduction.  I was able to look specifically at Tech because they are reporting the numbers locally for the school (to the Va Tech zip code).  I am not sure if other schools are.  I know W & M sent test kits to the students, who sent them back, so those will be reported as the home zip code I think.  In terms of the surrounding communities, ODU is now in line with UMW and VCU.  ODU is trending in the right direction whereas VCU and UMW are flat over two weeks.  W & M/ CNU are doing the best.  W & M is welcomed freshmen last week, as are some of the other schools.  The regional trends, which is good for W & M, CNU and ODU, but concerning for VT and GMU.  Also, JMU suddenly popped on the radar screen with positive grown, and is currently the highest growth rate in the state, but the Harrisonburg region is growing at less than 2%.


Note: this is a repeat from yesterday.

I want to get back to Vienna, locally.  Most of my readers are from Vienna.  I believe most of us are following protocols.  In, we are nearly 100% masked, and none of the nose exposed masks.  This is good.  Outside, while it is overall not crowded, people are generally not wearing masks.  The guidelines say 6-10 feet.  However, the virus follows physics not guidelines.  Two feet behind a person is safer (for me) than 10 feet in front.  Two people can probably stand safely back to back, at 1 foot, but not face to face at 6 feet.  The virus is carried with the breath.  The harder the breathing, the farther the breath will go (higher the velocity out of the mouth).  So, yelling at a sporting event is significantly riskier than sitting on a bench sipping coffee.  The mask mitigates the risk by capturing the larger particles, which is much more likely to contain the virus.    


Unfortunately, the state has not empowered the town to enforce the mask ordinance.  In commercial sites, the site manager can trespass a person and the police will enforce that.  However, particularly with the current social justice issues, I do not think the police enforcing mask wearing is optimal (Thank you Del. Keam for that perspective).  If you see a problem with a place that sells alcohol, The ABC office can enforce it.  Otherwise, the health department is in charge of mask enforcement, and that is a county organization, and they do not seem to follow up with calls.  Moreover, the problems observed at Waters field is not enforceable by the town, as the county owns the land and issues the permits.  I spoke with the person in charge of permitting and fields for the county, and there is no desire to enforce the governors mask ordinance; he was sympathetic to my concern and will send out reminders, but there is no desire to go beyond that.   If we want to change things, we need to look to the political leaders and not the county employees.  With that said, the town can only enforce the rules at, for example, Southside or Glyndon park.  But the offences that I have observed are at Waters field.  The funny thing is the leagues had to come up with a safe reopening plan (at least VGSL did), but that is not being followed.  


The best we can to is to focus on ourselves.  Wear the mask and be safe. This disease does not really discriminate. There is no shame in getting sick, but we all have an obligation to our community to stay healthy. Dr. Fauci says we may have a Vaccine by the end of the year, but it will probably not be until the second half of the year where the majority can be inoculated. Until that time, we are living with COVID. There are numerous studies that show there are potentially long-term effects for COVID (I say potentially because we are 8 months in to COVID-19 globally, and that is not long-term). Including neurological, cardiac, and respiratory issues. And that is with a mild case. Based on numbers from NYC, 1/34-1/40 people with antibodies end up hospitalized – which is presumably a life-threatening case. Some people say, but it only kills 0.5%, which does appear to be true. But 2.5-3.3% have life threatening cases. These are the numbers. If you do not believe me, look them up yourself: Total hospitalizations compared with total probable exposure based on Antibodies. 



While the mask your mask may not prevent your exposure, it will limit the viral load, which gives your immune system a better chance, and statistically may lead to less severe cases. 



This has been a difficult 5 months so far, and we probably have at least another 5 months to go before a vaccine is available. But anyone reading this is still alive. 170000 Americans are not.  Some say wearing a mask is a sign of weakness – of being a sheep.  I would rather be free to roam while wearing a mask than cooped up inside.


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

State Actions: Impact on Growth:  TBD

Figure Descriptions:  TBD

Other Sites: TBD


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