Post #715: Key graphs updated to 6/14/2020. Drop-off in new cases accelerates.

Posted on June 14, 2020

This post updates some key graphs to 6/14/2020.  Fairfax has seen a sharp dropoff in new cases.  We’ve been building up to that for the past couple of weeks, so that is not surprise.

As you can see from my just-prior post, my best explanation is that we’re finally seeing the seasonality of COVID-19 showing up in the data.  For sure, other than the Governor’s mandatory mask ordinance, it’s not like we’ve been doing hugely more to limit the spread.  And with just 1 person per 100 known to have been infected in Fairfax County (and likely no more than 5% of Fairfax residents actually having been infected), it’s far too soon for the “natural” end of the epidemic (typically estimated as herd immunity occurring with 70% of the population infected).

Whatever we’re doing under Phase I of re-opening, it’s not creating a spike in new cases.  If there are new cases attributable to this modest relaxation of restrictions, they are being swamped by this ongoing downward trend.

Impact of re-opening, Phase I, in Virginia, update to 6/14/2020.  New case growth is slowing all across Virginia, but it slowed more rapidly in the “late” opening areas.  As a result, we’ve now reached the point where there are fewer new cases coming out of the “late” areas (NoVA, Richmond City, Accomack County) than out of the rest of the state.

Here’s the graph of total cases.  You can see that the blue line (“late” areas) curves, so that at this point, the gap between the two is narrowing.

Source:  Analysis of county-level data as reported by the Virginia Department of Health.  NoVA plus is Northern Virginia, Richmond City, and Accomack County.  The latter is in the late-reopening group because because they had 500+ cases of COVID-19 in two poultry processing plants.

The story is a lot easier to see if I plot daily new cases, instead of cumulative cases.  That’s below, for the past month.  Over the past month, case growth in the late-reopening areas has slowed down to match that in the rest of the state, and now, with this most recent update, it has fallen below case growth in the rest of the state.

Read into those whatever you want to.  For myself, I find it hard to attribute anything on these graphs to the act of re-opening.  To me, having looked at health care data for much of my career, I’d say that whatever’s creating these new cases has more-or-less nothing to do with Phase I re-opening.

Hence my most recent post.  I think this is the seasonality of COVID-19, finally showing through the data now that things have stabilized in Virginia.

It’s too soon to tell whether Phase II of re-opening has any impact.  That only started on 6/5/2020 in the early-re-opening areas.  Under Phase II, e.g., restaurants and gyms are open for limited indoor service, and the (legally allowed) size of indoor gatherings increases to 50.

Source:  As above

A final note is that the late-opening areas still have more new cases per capita than the rest of the state.  So while the raw count of  new cases is about the same, the new cases per resident is still substantially higher in the late-opening areas. Data not shown.


Total cases, Vienna ZIP codes, data not shown.  I didn’t bother to update the graph.  As of 6/14/2020, we now have a total of 211 cases in ZIP 22180.  We had a total of four new cases show up over the last week in ZIP 22180.


Daily new cases, Virginia and Fairfax County, last 28 days, update to 6/14/2020.  The dropoff in new cases that started at the end of May continued.   The seven-day moving average is now down to 600 cases per day in Virginia, and 100 cases per day in Fairfax County.  As you can see from the graphs, that’s down from well over 1000 and about 300 per day, just two weeks ago.

Here’s the data tabulated by week, again updated to 6/14/2020.  Last week, Virginia’s new case count was half of what it was two weeks ago.  Fairfax’s was a third of what it was two weeks ago.