David Salzberg's Analysis of the COVID numbers for Virginia, focusing on Northern Virginia.
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Sept 15: Colleges are still where the action is.
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Daily Status, Sept. 15
Reminder: any sections that are unchanged since yesterday are grayed out.
Note: the number of deaths in VA jumped significantly, about 3% yesterday. VDH reports they are clearing a backlog in such reports.
Situational Awareness
Across the commonwealth of Virginia, there were 943 reported new cases of COVID-19. The number lower than the recent trends; but in line with weekend numbers standard deviations below the mean. Overall, cases are essentially flat (-0.3%) for the last three weeks. It is worth noting that, over over that time, 17% of the positives have been from colleges; today, colleges account for 14% cases are. Without the college cases, the numbers be decreasing slowly. Regionally, all districts showing negative growth. The testing numbers across the state remain ok, but not great, at around 5.5% positive which is approaching the desired 5.
We continue to see enhanced cases across age groups in in the vicinity of Va Tech & Radford (New River Health District), and JMU (Central Shenandoah Health District)(JMU) suggesting the college outbreaks are spreading to the local populations. This is concerning for two reasons: 1) the local population in these rural areas tend to not practice social distancing that well, and 2) more vulnerable populations are exposed.
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 those that did brought the disease home. The VT outbreak continues to grow, as does the smaller UVA outbreak. And there are some preliminary indication of an outbreak at ODU.
Outside of college towns and a few smaller cities/towns, the state is doing well. In fact over the last three weeks, 16% of the probable active COVID cases are affiliated with a the colleges of JMU, VT, UVA, and VCU; those colleges account for 1.5% of the population. Radford is finally improving.
Regions:
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 Central, SW, and NW parts of the state.
Regional growth rates are (in fraction per day) continue to to show improvement.
NOVA: .991 -- GMU
Central VA: 1.000-- VCU
Hampton Roads/Eastern VA: .965-- W&M, CNU & ODU
SW VA: 0.969 -- VT & Radford
NW VA: 0.992- 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)
Region
Last month
Last week
NOVA
9.4
8.7
Eastern
10.5
10.4
Central
11.6
14.0
NW
10.2
16.1
SW
16.4
17.1
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. The dive in the last two days may be the result of the weekend low numbers in NW & Central CAB. Again, SW VA, even with the lower population, has roughly the same number of cases than any other region. It must be noted, though, that the apparent drops is NW and SW may be a 1 day effect of limited reporting on the weekend.
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. Note that hospitalizations and deaths remain much lower than the peak in May.
Currently, the all jurisdictions are improving, with those inside the beltway doing the best.
Fairfax Co.: 0.993
Arlington Co.: 0.980
City of Alexandria: 0.971
Prince William Co.: 0.995
Loudoun Co.: 0.985
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 three 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. Clearly the enhanced enforcement (or threat of enforcement) is working. Other jusridictions could learn from Alrington.
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.
Northern VA overall is down a bit. Vienna is still showing an increase, which it's baseline rate from about 4 cases a day/100,000 one month ago to about 8-9 cases per day now. If you look at the Fairfax county chart, Vienna is no longer the part of the county with the least transmission. I do not spend enough time in other parts of the county to assess the behaviors, but I have seen/observed less social distancing in Vienna (including mask wearing), except inside stores. I am concerned that, as a community, we are setting ourselves up for a tough autumn.
Region
Last month
Last week
Growth rate (%/day)
Fairfax Co
Vienna
5.4
7.9
1.3
McLean
4.9
3.6
-3.0
So. Alexandria
11.9
9.4
1.2
Reston/Herndon
8.5
8.5
0.3
Annandale/Fall Church
12.2
8.7
-2.8
Fairfax
7.6
5.7
-3.6
Arlington/Alexandria
No. Arlington
6.9
5.7
0.9
So. Arlington
11.7
9.7
4.7
Alexandria City
13.4
9.8
-4.8
Looking at the data, it is possible that the surge in Vienna was related to infected JMU students returning home, but if that is the case, I would expect the other parts of northern VA to show a similar uptick.
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 0.99 1.01 0.99 0.99 1.00
AllVA 0.99 1.02 0.99 0.99 1.00
Colleges:
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, 1 at VT and 1 at Radford. 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 10:43 AM 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.
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**
Dashboard Cases
% of population infected ***
Va Tech
21.1
988
3758
727
10.6
GMU
2.8
13
30
19
0.1
UVA
11.7
191
553
321
2.4
ODU
8.0
37
59
16*****
0.2
JMU
37.8
1159
5416
1349
25.5
CNU
6.2
0
0
2******
0
UMW
6.6
0
0
4
0
Radford
37.1
545
2655
357*****
33.5
VCU
0.8
147
304
220
1.0
W&M
1.9
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%.
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. In the current state, where things are stable, I may move Radford to the watch list.
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 38% 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.
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. 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.
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.
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 5. It is worth noting that pre-arrival testing has identified 20 cases, which were not allowed on campus. W&M shows 2800 tests in the last week; it is not clear if that includes the retesting of the earlier student tests; they also report 0.29% positive. That suggests 8 positive tests, but it appears that some (4) were not on campus yet (I may be over parsing the data). The 2800 tests -- that is the retesting of the student body -- did not show up in the Williamsburg numbers. W&M tested all students prior to arrival in town.
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 51 cases on campus, which is about what I would expect based on non-tested students. 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 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.
Commentary:
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 seenhere.
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.
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.
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