Daily Update, Sept 12: evidence for college students infecting the senior citizens?


Daily Status, Sept. 12

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

Changes for today: 1) I modified my approach on estimating the number of cases based on % positive. 2) I have added growth rate to the local activity tables. 3) I am exploring age distribution of cases in the regions with college outbreaks.

Summary/Situational Awareness

A scenario that is potentially really dangerous in unfolding some regions with college towns:  it looks like the cases are moving from the student population to the general (and in particular senior) population.  I am not sure of the mechanism.  But the numbers are showing a sharp increase in senior citizen cases in the health districts containing JMU, VT & Radford.  There is a lesser increase middle aged people.  

With that said, it It looks like some colleges are either getting a handle on the virus or achieved herd immunity: Radford and VCU are stable now.  Unfortunately, the outbreak at JMU continues to spread; only about half the students returned home. And VT is spiraling out of control;  UVA could be next. 

Across the commonwealth of Virginia, there were 1300 reported new cases of COVID-19.  The number higher than the recent trends; it is between 1 & 2  standard deviations above the mean.     Overall, cases are growing slowly flat for the last three weeks. It is worth noting that, over over that time, 16% of the positives have been from colleges; today,  colleges account for 22% (284) of the cases are directly related to college; without the college cases, the numbers would be decreasing by 1%/day Regionally, only NW VA is increasing, largely the result of the outbreak at  JMU & UVA. SWVA has stabilized because the Radford outbreak is decreasing faster than the VT outbreak is spreading The testing numbers across the state remain ok, but not great, at around 6-7% positive.  I would like to see the overall positive rate under 5%

Outside of college towns and a few smaller cities/towns, the state is doing well. In fact over the last three weeks, 14% of the probable active COVID cases are affiliated with a the colleges of Radford, JMU, VT, UVA, and VCU; those colleges account for 1.5% of the population.


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 rural SW and NW parts of the state.  The week over week numbers in SW VA are starting to stabilize, mostly from the numbers at Radford decreasing.

Regional growth rates are (in fraction per day) are primarily impacted by anomalously low case numbers the last two days, probably the result of the holiday.

NOVA: .995 -- GMU

Central VA: .996 --  VCU

Hampton Roads/Eastern VA:  .964-- W&M, CNU & ODU

SW VA:  0.991 -- VT & Radford

NW VA:  1.013-- JMU & UVA


The state as a whole is is increasing at 1.005.

Daily case count per 100,000 is a often sited metric (below 10 (0.01%) statewide would take VA off the quarantine list .  The following table shows the number per 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
















The following charts are for the 5 regions/trends.  For the last month or so, we note that NOVA have been flat at around 300 cases per day, Hampton Roads (Eastern) drummed from about 800 to under 300 .Again, SW VA, even with the lower population, has mother-in-law same number of cases than any other region.  Note that in the "line plots", I adjusted the dates a bit, and added a number for the last three weeks, since I often site that number.

Local/Northern VA:

Northern VA has returned to the trend; the low case counts were, as expected the result of the holiday weekend.  In the trends, we can either describe it as slow growth since late June, or flat since early august.  Both equally describe the data.

Currently, every Northern Virginia jurisdiction is either flat or showing a decrease.  

Fairfax Co.: 0.993
Arlington Co.: 0.965
City of Alexandria: 0.995
Prince William Co.: 1.000
Loudoun Co.: 1.003

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 14 day ago, Arlington began enforcing social distancing guidelines. Since then, there trend has gone from 1% per day to -5% per day.  Now, Arlington is doing the best; Alexandria and PW are doing worse.

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. For example, Vienna/Oakton has more cases than Fairfax. 

I added an estimate of the growth rate;  Northern VA overall is down a bit, with the notable exception of Vienna which is seeing a 100%increase is cases over the last week (6.8% per day over the last several weeks).  Vienna is still below the statewide average, but Vienna is trending in the wrong direction.


Last month

Last week

Growth rate (%/day)

Fairfax Co









So. Alexandria








Annandale/Fall Church









No. Arlington




So. Arlington




Alexandria City




Note that the current up trend in Vienna is concerning.  The increase is being driven by all of the ZIPCodes. Vienna is still at about 1/2 the case load of the May peak, when we were averaging about 18 cases/1000.;   It is also possible that some college students listed the home address with off-campus covid tests, but that should be effecting other parts of the regions in a similar manner. 

Age Distribution: 

Right now, the age distribution in Northern VA is showing the impact of sending the on campus (mostly freshmen) home from JMU.  There are about about 50 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), 50 cases actually seems low to me.  The concern is that the JMU students will infect there families.  If that happens, we will know it in a week or two. 

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

             <10    0-19.  20-39.  39-59.  60+
  NOVA  1.00    1.02    0.99      0.98   1.00
  AllVA   1.00    1.04    1.00      0.99   1.00


Before I get into details, there are at least three COVID hospitalizations in colleges that are from ages consistent with college students.  2 at JMU,  and 1 at VT.  There could be more, if upon admission, the student gave the home address.  There are also ad hoc reports of students in observation in Harrisonburg.

My process combines the VA Department of Health data and what is reported by the colleges.  The report is as of 11:42 AM ET.  I need to point out that the VDH cases may include cases not affiliated with the university as I am using geographic survaliance

RED means there is clear evidence for community spread
YELLOW means there may be community spread; still ambigious
GREEN means no evidence of community spread
BLACK means they went online.


% Positive

VDH Cases*

Estimates Cases**

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:

RADFORD (linked to the university Dashboard)

The numbers of new cases at Radford seems to have peaked.  We do not know how many people have/had the disease.  Because the percent positive remains as high as it is, though, most of the people who need to be tested might not be able to be tests (or at least might not have been able to get tested in the last several weeks). The number of new cases is high, but not growing -- and possibly shrinking.  At this point, my only recommendation is to perform serology/antibody studies to retrospectively determine the number of cases.   Radford tested the students prior to arrival, but allowed students on campus prior to the test results.  


JMU is going online.  JMU has been fairly transparent with the situation, but could not get ahead of it.  At this point, it is mitigation. They sent the healthy students home, and are allowing the positive to stay on campus, which is critical for society as a whole   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.
We have seen the prevalence of the virus in Blacksburg increase with the return of the students. Each day, there are more than 60 new cases validated.  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% of the student body is positive.  Short of a two week pause, I am not sure how Tech will contain the spread. One week ago, VT claims there is no uncontrolled community spread, but the data does not support that assertion. Virginia Tech tested only on-campus students.  
With the students return, there has been a marked increase in cases.  It appears there is community spread. And it is growing, at an increasing rate.  large scale community spread, if it occurred, should show up in the next several days  Between the increase in the percent positive and the absolute numbers increasing, UVA is trending in the wrong direction.  UVA tested all students prior to arrival on campus.

Watch List: 


VCU seems to have the virus under control -- it was promoted from RED to YELLOW.  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.   

Other schools:

William & Mary -- so far so good -- No evidence of community spread.  There are now cases on campus (I think).  I am assuming they have somewhere between 1 and 9 cases; looking at the numbers for Williamsburg, it is probably 1 or 2. It is worth noting that pre-arrival testing has identified 20 cases, which were not allowed on campus. W&M is retesting all students this week. W&M tested all students prior to arrival in town. 

CNU -- Students have been back upto 1 month. A few cases.  Under control.

ODU -- Nothing noteworth.  My concern with ODU is they did not test the students, so there may be asyptomatic/presymtomatic spreaders on campus (see JMU).  There dashboard is a week old, which would be concerning, but the data suggests there can not be more than a 20 cases total, which is below what I can resolve because of the noise level.

UMW -- Not open yet.

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 1 week ago, 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.  The numbers are small, but it is very concerning because that age groups does not have a good outcome.  


The CDC did a study comparing a group that contracted COVID to one that did not.  The key finding were dining in bar/restaurants (not takeout) correlated with COVID exposures, particularly when masks were not worn.  That was the second riskiest activity identified, second only to having an infected family member in the house.  The study can be seen here.

I try to be apolitical in this blog, but today, I want to say:  we need to demand honesty from our national leadership with the pandemic.  When our leaders are talking about "not panicking the people" what they are saying is we unable to make informed decisions about the disease or other things.  

Also, Masks are our friends.  Masks significantly reduce the risk of disease transmission, if they are worn correctly.  The purpose of masks are 1) to contain any virus you may discharge through breathing, talking, coughing or sneezing, and 2) to protect you from incoming viruses with your breathing.  In order for the mask to function, it must cover the mouth and nostrils.  The chin and neck do not need protection (unless you have a tracheotomy).  I am seeing too many people with the nose and/or mouth exposed.  And I have even seen town employees with the masks that way.  Confronting does not seem to work, except sometimes with a neck mask, people just forgot to put it on.   It is not enough to have a mask; it most be worn properly.  WHO put the following graphic:

I try to keep my political biases out of it.  Unfortunately, some politicians have turned data into a political issue.  Yesterday, while driving home, I heard a prominent politician state that the America's numbers would be much better if we excluded NY.  I am not sure when the quote was captured.  But, I am a data and science person; based on that, I wonder how policy can follow when data is fabricated.  The data for cases in the USA, with and without NY are shown below. In April, our cases there about 50% NY, since then NY has been doing better.  Since June 1, NY has accounted for 1.5% of the cases nationally, even though it has 5.8% of the population.  So, currently, NY is outperforming the country.  Even including the early days, NY is at 7.2% the cumulative cases, about 25% higher than you would expect.  By comparison, Florida accounts for 10.2% of the cases but 6.3% of the population.  And FL should have known better.  (VA is at 2% of all cases, and 2.5% of the population).

The numbers do not lie.


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

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:


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