Post #1233: Introduction to Virginia data on school outbreaks of COVID-19, a quick note.

Posted on September 4, 2021



This post looks at Virginia Department of Health information on outbreaks of COVID-19 in K-12 schools in Virginia.  Virginia not only tracks total outbreaks in schools, in most cases, it allows you to check on-line regarding the progress of an outbreak in an individual school.  Links given below.

The 2021-2022 school year so far.


Source:  Virginia Department of Health COVID-19 dashboard.

I’m looking into Virginia’s data on outbreaks because it should, in theory, tell us something about the spread of COVID-19 in K-12 schools. Above, you can see the count of outbreaks in K-12 schools, by week, for the past half-year.  (The last blue bar — the week of data — is incomplete).

The data look reasonable, in the sense that you can see the summer break clearly mirrored in the heights of the bars in the graph.  Left to right, you see the end of the 2020-2021 school year, some low counts during the summer, and then the start of the 2021-2021 school year in August 2021.

By eye, the 2021-2022 school year, through the end of August, doesn’t look any worse than last spring.  But not all school districts are in session yet, so you really can’t make a valid comparison to last year.

In any case, it’s that information, in various levels of detail, that I’ll be talking about in this post.

A deeper dive into the available data

Source:  Virginia Department of Health, links given below.

The Virginia Department of Health tracks COVID-19 outbreaks in a variety of settings.  Settings include K-12 schools, colleges, nursing homes, daycare, prisons, and health care facilities.

Virginia uses a national definition of “an outbreak” in an educational setting (downloadable at this link).  That boils down to two or more cases, within a school, where school was the only likely place where the disease could have been transmitted from one to the other.

Two or more laboratory-confirmed COVID-19 cases among students or staff with onsets within a 14-day period,who are epidemiologically linked, do not share a household, and were not identified as close contacts of
each other in another setting during standard case investigation or contact tracing.

Directors of those organizations are legally required to report known or suspected outbreaks of any of several diseases, including COVID-19.  I could not identify any penalty for non-compliance laid out in the law, and I have no idea how complete the reporting is.

Virginia supplies information on outbreaks in facilities in a variety of ways, including a data dashboard, some customizable on-line tables, and downloadable data files.

Probably the most important, for parents, is to be able to check the progress of any active school outbreaks in your area.  You can do that on the customizable list of individual outbreaks is at this link.   Note that you can only check on outbreaks that have occurred since August 1, 2021 on that web page.  (E.g., nothing is listed for Fairfax County, VA, presumably because no reported outbreaks have occurred there in the last month).  Detailed information on earlier outbreaks appears to be available only on a downloadable data file.

Today (9/4/2021), selecting for “outbreaks in progress” and K-12 schools yields about 15 known, active outbreaks in K-12 schools in Virginia.  Another six are “pending closure”.

The data are something of a mishmosh.  In some cases, one line is reported for a school.  In other cases, one line is for an entire school district.  In other cases, a school football team gets its own line.

You can also check on any reported outbreaks on college campuses using this same tool.  Any outbreak with five or fewer cases will show an asterisk instead of the actual case count, as a privacy protection measure.

Keep in mind that this is a count of outbreaks, not a count of all COVID-19 cases.    You cannot use this lookup to determine if any COVID-19 cases have been found among students at some particular school.

The presence of one (or many) COVID-19 cases at a school is not necessarily counted as an outbreak.  COVID-19 cases in a school are only counted as an outbreak if a) there are two or more cases around the same time, b) those individuals had some sort of close contact at that school, and c) they didn’t have any sort of close contact in any other setting.  In other words, it’s only an outbreak if the only likely place it could have been spread was at school.


Downloadable data.

Virginia provides several downloadable data files, but there are some significant limitations to what is provided.

First, the same information discussed above — facility-level outbreaks data — is now available as a downloadable file.  Apparently, some legal requirement for that information was dropped, and Virginia stopped producing the file for a while.  It has now been restarted, and contains new outbreaks from August 1, 2021 forward.

Otherwise, in terms of tracking school outbreaks, Virginia provides:

  • Running total of outbreaks, by date, by health district (at this link).
  • Daily count of new outbreaks by health region (at this link).

It appears that the facility-level detail file could be aggregated up to the county level.  So, in theory,  one could get total school outbreaks, and outbreak cases, by report data and county, by aggregating that file.  The only limitation is that any outbreak with fewer than five cases at time of report will have the case count missing (replaced with an asterisk, as a privacy measure).

School calendars.

The other piece of information I need to examine the start of the 2021-2022 school year is a comprehensive set of Virginia school district calendars. For example, to compare the August 2021 data (presented at the top of this posting) to last year’s data, you need to know what fraction of schools were open in August.

The Virginia Department of Education produced such a listing last year, but I have not yet found one for the 2021-2022 school year.

Worse, as I started spot-checking dates by looking up individual school districts, and last year’s opening days are a poor guide to this year’s.  Presumably, the reaction to the pandemic last year moved a lot of school opening dates.

In theory, I could look up each individual school district starting date for the 2021-2022 year, but that’s just too much work.  I’m hoping the Virginia Department of Education will produce that consolidated calendar document again this year.