Alissa Eckert, MS; Dan Higgins, MAMS

The Commonwealth of Virginia continues to deal with COVID-19 (Coronavirus Disease 2019), a respiratory illness that originated in Wuhan, China, last year and has since spread throughout the world. In an effort to slow the spread of the disease in the Commonwealth, Governor Ralph Northam (D-VA) has ordered many nonessential businesses closed and imposed other restrictions.

The Virginia Department of Health (VDH) provides current information about this outbreak on their web site, which is a useful and informative reference. I began this post when VDH removed their chart of day-by-day increases in cases, which they have since restored, but they still do not provide the equivalent charts of hospitalizations or deaths. They also do not post a chart of the doubling rates.

I am making this post to provide citizens of the Commonwealth with this important information. These charts are all based directly on official data provided by VDH. There are some data anomalies present in VDH data; I do not correct or ‘massage’ any of the data so those anomalies are present in the charts below. I will update each of the charts as time permits.

Virginia Statewide

Total Cases (Virginia)

The most obvious method of tracking the spread of COVID-19 in Virginia is to just track the total number of verified cases. This is a useful measure, but it lacks a lot of important context.

First of all, it will always be going up, since every new case increases the cumulative total. This makes it difficult to visualize whether there are changes in the rate of increase. Second, it is difficult to distinguish how much of the increase is actual new cases and how much is connected just to the availability of testing.

You can, however, get a general idea of whether the overall ‘curve’ is exponential or linear. Virginia’s curve at this point appears to be linear, which is strong evidence that our mitigation efforts have worked.

Cases Per Day (Virginia)

A more useful measure is to look at how many new cases are identified each day. This filters out the main problem with the ‘total cases’ chart (namely that it doesn’t show changes in the trend very well) . . . but it is still very difficult to tell how much of the increase is due to real spread of the virus and how much is due to the increased availability of testing.

The cases-per-day now appears to be on a plateau, though this is likely caused by increased testing capacity. We are likely actually past the peak in cases, evidenced by the continuing downward trend in percentage of tests returning positive. The solid blue line represents a seven-day moving average, which helps filter out day-to-day swings. The darker blue/gray line shows a seven-day moving average of the percentage of COVID-19 tests returning positive.

(Note: The daily test positive rate data from VDH often has a one or two day delay, which is why the daily test positive rate may have one or two missing data points at any given time.)

Total Hospitalizations (Virginia)

Tracking the total number of COVID-19 hospitalizations in Virginia is likely a better measure than tracking the raw total of cases. We can assume that the rate of hospitalizations as a percentage of total cases is pretty consistent from day to day, and it is much easier to track accurately than total cases. It may also be more accurate than the tracking of deaths due to some questionable reporting standards (described below in that section).

This doesn’t give us a way to calculate how many infections there really are (since we don’t have firm, reliable data on what percentage of cases are asymptomatic) . . . but it does serve as a reasonable proxy for the shape of the curve and whether it is exponential or linear.

The overall shape is very similar to the chart of the total number of cases, and is definitely linear rather than exponential, which is additional evidence that our mitigation efforts have worked.

Hospitalizations Per Day (Virginia)

Like the number of new cases per day is probably a better measure of progress than the raw chart of total cases, likewise a chart of new hospitalizations per day is more useful than the chart of total hospitalizations.

Here there is a much clearer indication that Virginia’s curve has flattened out. After a lengthy plateau, it is now clear that we are past the peak and new hospitalizations are trending downward. The percentage of occupied hospital beds utilized by COVID-19 patients has held consistently below fifteen percent, and total hospital utilization has been mostly steady near seventy percent, although it is trending gently upwards after nonessential medical procedures were permitted again.

The solid orange line represents a seven-day moving average, which helps filter out day-to-day swings. The dark line shows the total percentage of available hospital beds currently being utilized (for all reasons). The golden line shows what percentage of total occupied beds being utilized by COVID-19 patients.

Total Deaths (Virginia)

Some argue that tracking deaths due to COVID-19 is the most accurate measure of the spread of the disease in Virginia, since it is likely that nearly every death gets reported. But the Centers for Disease Control (CDC) and state guidelines for counting deaths as COVID-19 deaths seem . . . questionable. There is an important distinction to be made between somebody dying of COVID-19 and somebody dying with COVID-19, and this does not seem to be properly accounted for.

There is a lot of gray area. For example, if somebody with an existing cardiovascular illness contracts COVID-19 and then dies, how do you determine with certainty whether they died of their existing illness, or COVID-19, or both? In my opinion, this is an important measure, but is not as accurate as the measure of total hospitalizations.

Deaths Per Day (Virginia)

Just as total cases and total hospitalizations per day are more useful measures than the raw counts, the number of deaths per day is more useful than the raw count of deaths. This is, however, affected by the questionable reporting practices described above. Also, because the numbers are much lower than the numbers of cases and hospitalizations, it is more subject to wild swings that don’t represent the actual trends.

But here, too, things seem to be getting better, and it is becoming increasingly clear that we are past the peak in deaths statewide, although it does appear to be having a bit of a rebound at the moment. The solid green line represents a seven-day moving average, which helps filter out day-to-day swings.

Doubling Rates (Virginia)

All of the above charts are useful and help us to understand how things are going in Virginia’s effort to limit the spread of COVID-19, but the gold standard—which gets far too little attention in the mainstream press—is the chart of changes in the “doubling rate.”

In this case, where our data has granularity to the day, we are interested in how many days it is expected to take for the number of cases, hospitalizations, and deaths to double. To calculate this, you figure out each day what the percentage increase in cases, hospitalizations, or deaths is, and figure how many days it would take based on that rate for the total number to double.

You want this number to increase, since a higher number of doubling days means that the spread of the virus is slowing down. In order to illustrate this consistently with the above charts, I have inverted the Y axis.

Because this is a fairly abstract calculation that is heavily influenced by day-to-day fluctuations, I have charted these values as a scatter plot and emphasized the seven-day rolling average. Known cases, hospitalizations, and deaths are all included in a single chart.

Here we can see that things are getting better, not worse, in the Commonwealth of Virginia. The doubling rate is increasing, which is what we want to see. All of the rates are now averaging above twenty days. This is strong evidence that we are past the height of the epidemic and can loosen many restrictions.

Loudoun County

Total Cases (Loudoun)

The county-level number of cases suffers from the same problems as the sitewide equivalent. It, too, will always be going up, since every new case increases the cumulative total, and it is difficult to distinguish how much of the increase is actual new cases and how much is connected just to the availability of testing.

You can, however, get a general idea of whether the overall ‘curve’ is exponential or linear. Loudoun’s curve at this point appears to be linear, which is strong evidence that our mitigation efforts have worked.

(Note: There is a data anomaly in the VDH reporting for May 24, 2020, where the total number of cases in Loudoun County dropped by ten from the day previous. This anomaly remains uncorrected in the VDH data and is shown in the chart below.)

Cases Per Day (Loudoun)

A more useful measure is to look at how many new cases are identified each day. This filters out the main problem with the ‘total cases’ chart (namely that it doesn’t show changes in the trend very well) . . . but it is still very difficult to tell how much of the increase is due to real spread of the virus and how much is due to the increased availability of testing.

Loudoun’s cases-per-day trend is probably past the peak, but large testing events in recent days have caused an artificial spike. The solid blue line represents a seven-day moving average, which helps filter out day-to-day swings. The darker blue/gray line shows a seven-day moving average of the percentage of COVID-19 tests returning positive, which is averaging below twenty percent and continuing to trend downward.

(Note: The daily test positive rate data from VDH often has a one or two day delay, which is why the daily test positive rate may have one or two missing data points at any given time.)

Total Hospitalizations (Loudoun)

Tracking the total number of COVID-19 hospitalizations in Loudoun is likely a better measure than tracking the raw total of cases. We can assume that the rate of hospitalizations as a percentage of total cases is pretty consistent from day to day, and it is much easier to track accurately than total cases.

This doesn’t give us a way to calculate how many infections there really are (since we don’t have firm, reliable data on what percentage of cases are asymptomatic) . . . but it does serve as a reasonable proxy for the shape of the curve and whether it is exponential or linear.

The overall shape is very similar to the chart of the total number of cases, and is definitely linear rather than exponential, which is additional evidence that our mitigation efforts have worked.

Hospitalizations Per Day (Loudoun)

Like the number of new cases per day is probably a better measure of progress than the raw chart of total cases, likewise a chart of new hospitalizations per day is more useful than the chart of total hospitalizations.

Here too it appears that Loudoun County is on a plateau. The solid orange line represents a seven-day moving average, which helps filter out day-to-day swings. It is unclear why there was a massive one-day spike recorded on May 13; I suspect this is just a tracking anomaly.

Total Deaths (Loudoun)

As described in the statewide summary of total deaths, the Centers for Disease Control (CDC) and state guidelines for counting deaths as COVID-19 deaths seem . . . questionable. There is an important distinction to be made between somebody dying of COVID-19 and somebody dying with COVID-19, and this does not seem to be properly accounted for.

In addition, there have been so few deaths in Loudoun County compared to the statewide numbers that it is almost impossible to discern any trends. This chart is not very illuminating, but is included for completeness.

(Note: There is a data anomaly in the VDH reporting for May 29, 2020, where the total number of deaths in Loudoun County dropped by one from the day previous. This anomaly remains uncorrected in the VDH data and is shown in the chart below.)

Deaths Per Day (Loudoun)

Just as total cases and total hospitalizations per day are more useful measures than the raw counts, the number of deaths per day is more useful than the raw count of deaths. This is, however, affected by the questionable reporting practices and small numbers described above.

Here, too, it is almost impossible to discern any trends. This chart is not very illuminating, but is included for completeness. It should be noted that there have been a handful of very large single-day reports (relatively speaking); the reason for this is not clear.

Doubling Rates (Loudoun)

The gold standard for tracking the process of the epidemic is, as described in the statewide report, the chart of changes in the “doubling rate.” How these numbers are computed is described above and is not repeated here.

Because this is a fairly abstract calculation that is heavily influenced by day-to-day fluctuations, I have charted these values as a scatter plot and emphasized the seven-day rolling average. Known cases, hospitalizations, and deaths are all included in a single chart.

Here we can see that things are getting better, not worse, in the Loudoun County. For some time we were lagging the statewide numbers, but we appear to now be even with or even out-performing the state. All of the doubling rates are now averaging over twenty days. Loudoun County is now well positioned to enter Phase 1 along with much of the rest of the state.

Restrictions In Place

Citizens of Virginia are under a number of emergency orders and restrictions. To the best of my knowledge, the following list includes all orders currently in effect that are likely to have noticeable impacts for the average Virginian. I skipped the orders that only affect a very limited audience (such as those dealing with temporary changes to medical licensing). This list will be updated when new orders are issued, or old ones expire or are rescinded.

Executive Order 51 (declaration of a state of emergency)

  • Effective: March 12, 2020
  • Expires: June 10, 2020 (unless amended or rescinded)
  • Summary:
    • Activates the Virginia Emergency Operations Center and the Virginia National Guard.
    • Allows for the temporary waivers of state requirements and regulations.
    • Authorizes state funding for emergency response.

Executive Order 61 (school and business restrictions)

  • Effective: May 15, 2020 (May 29, 2020, in the Northern Virginia region, City of Richmond, and Accomack County)
  • Expires: June 10, 2020 (unless amended or rescinded)
  • Summary:
    • Closes restaurants and other dining establishments except for delivery, take-out, and outdoor dining. Outdoor dining must be for no more than fifty percent capacity, no groups larger than ten may be seated as a party, and parties must be seated at least six feet apart.
    • Requires that essential businesses defined in the text of the order, if they remain open, must provide employees with face coverings.
    • Requires any nonessential businesses that remain open to operate at less than fifty percent capacity. Employees must wear face coverings and social distancing must be enforced. This includes personal care and grooming businesses, as well as indoor shooting ranges.
    • Closes fitness and exercise facilities except for outdoor activities with social distancing and other requirements imposed.
    • Closes recreation and entertainment businesses including theaters, concert venues, museums, bowling alleys, and amusement parks. Closes beaches except for fishing and exercise. Requires campgrounds that remain open to enforce least twenty feet of distance between campsites.
    • Prohibits all public and private gatherings of more than ten people.
    • Closes K-12 schools for the remainder of the school year. Closes higher education institutions to in-person instruction and gatherings of more than ten people.
    • Requires any religious services held to limit attendance to percent capacity with social distancing and other restrictions imposed.

Executive Order 63 (face coverings)

  • Effective: May 29, 2020
  • Expires: Unknown (in effect until amended or rescinded)
  • Summary:
    • All people over the age of ten must wear a face covering when entering, exiting, traveling through, or spending time in most public places of business, public transportation, government buildings, and other indoor places outside the home. There are exceptions for eating and drinking, exercising, and persons with health conditions that prohibit face coverings.

Summary

Most of Virginia

Across the Commonwealth of Virginia, the ‘curve’ of the COVID-19 epidemic has been flattened and we are passed the peak. The doubling rates are now well above fourteen days and most of the key metrics are trending downward. Those that are not are likely only because of changes in tracking and increased testing availability.

Most of Virginia met the key criteria for Phase 1 reopening on May 4, 2020. Governor Ralph Northam (D) did not permit the state to begin entering Phase 1 until May 15, eleven days late.

Most of Virginia met the key criteria for Phase 2 reopening on May 18, 2020. Governor Northam has not yet allowed the state to begin entering Phase 2.

Most of Virginia met the key criteria for Phase 3 reopening on June 1, 2020. Governor Northam has not yet allowed the state to begin entering Phase 2, let alone Phase 3.

If trends continue, most of Virginia will meet the key criteria for a complete reopening on June 15, 2020.

Governor Northam should allow most of Virginia to begin Phase 3 reopening immediately, excluding only those specific jurisdictions that do not yet meet the gating criteria.

Loudoun County

In Loudoun County, we lagged the statewide numbers earlier on but appear to have ‘caught up.’ Loudoun County has been unnecessarily ‘bundled’ with other Northern Virginia jurisdictions that are lagging.

Loudoun County met the key criteria for Phase 1 reopening on May 11, 2020. Governor Northam and the Loudoun County Board of Supervisors did not permit the county to begin entering Phase 1 until May 29, eighteen days late.

Loudoun County met the key criteria for Phase 2 reopening on May 25, 2020. Governor Northam and the Loudoun County Board of Supervisors have not yet allowed the county to enter Phase 2.

If trends continue, Loudoun County will meet the key criteria for Phase 3 reopening on June 8, 2020.

If trends continue, Loudoun County will meet the key criteria for a complete reopening on June 22, 2020.

Virginia Governor Ralph Northam (D) should modify Virginia’s policies to allow county-by-county management of our mitigation efforts based on the actual conditions in each locality, and impose only the minimal necessary restrictions given those conditions.

Changes in Reporting

  • April 29, 2020:
    • Added a summary of official restrictions in Virginia.
  • May 1, 2020:
    • Charts of day-to-day changes will now feature a seven-day rolling average line (was previously a three-day rolling average).
    • All charts now feature markers indicating important changes in statewide restrictions and federal guidance.
    • In addition to statewide charts, this post now also includes the equivalent charts for only Loudoun County.
    • Addition of a brief summary of progress.
  • May 10, 2020:
    • The Virginia cases-by-day chart will now include Virginia Department of Health data about the percentage of tests returning positive.
    • The Virginia hospitalizations-by-day chart will now include Virginia Department of Health data about the total utilization of available hospital beds, and the percentage of those utilized beds being used by COVID-19 patients.
  • May 16, 2020:
    • The tracking of positive cases per day typically lags the other data by one day. Due to a spreadsheet error, this was not correctly shown in the chart. This issue has been corrected.
  • May 18, 2020:
    • Tracking of positive cases per day will now be primarily in a rolling seven-day average for easier comparison with other metrics. The actual values are now shown on the chart as scatter plot markers.
    • Tracking of positive cases per day is now displayed on the Loudoun County cases per day chart, as this information is now available in the VDH data sets.

References

This post is being updated with new information as it becomes available.