Covid-19 US cases by counties following political rallies

The list of rallies is from  https://en.wikipedia.org/wiki/List_of_post-election_Donald_Trump_rallies where I have added the county, its population, and where available, estimates of the number of attendees.

General Election rallies (June 2020–present) 

Method

We are interested in whether some of these events may have served as 'super-spreader' events. 

The raw data we analyze is the Johns Hopkins University daily confirmed cases data for the US available at:  https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_confirmed_US.csv

The question is whether there was a significant rise in confirmed Covid-19 cases after the rally, in particular in the 2-14 days following the rally (according to the CDC, Sep 18, 2020: "Symptoms may appear 2-14 days after you were exposed to COVID-19".

The social distancing at the rallies was minimal, and not everyone wore masks, see the photos below taken at the Oshkosh rally.

Impacted counties

We look at the adjacent counties in the same state (using https://gisgeography.com/us-county-map/) we see the following counties:

First, we just look at the number of daily confirmed cases for the county in which the event was held. 

Observations:

• The smoothed daily confirmed cases indicated marked increases in the cases as follows

  County	State	date of event	date of a noticeable increase in cases	magnitude of increase	delay	peak
  Blue Earth	Minnesota	8/17/2020	8/27/2020	3x increase in cases/day	10 days	9/03/2020
  Lackawanna	Pennsylvania	8/20/2020	8/29/2020	3x increase in cases/day	9 days	9/04-15/2020
  Rockingham	New Hampshire	8/28/2020	9/10/2020	2x increase in cases/day However no cases were linked to the rally by Sept 11.	13 days	9/12-17/2020
  Winnebago	Wisconsin	8/17/2020	8/28/2020	2.5x increase in cases/day	11 days	9/18/20
  Westmoreland	Pennsylvania	9/3/2020	9/12/2020	No apparent increase
  Saginaw	Michigan	9/10/2020		No apparent increase
  Douglas	Nevada	9/12/2020
  Marathon	Wisconsin	9/17/2020

  The sharp rise in Winnebago county from about 12 confirmed cases/day before the rally to over 80 new daily cases reported on 8/19/2020 is a concern. 

And the confirmed cases for those counties is below, the dates in the title boxes are the date of the rally.

Minden, Douglas County, NV 9/12/2020	Henderson, Clark County, NV 9/13/2020	Oshkosh, Winnebago County, WI 8/17/2020
Observations: There is a rise in cases in 4 of the 5 counties starting a few days after the rally.	Observations: Clark, Mohave, and Nye counties all see a rise in confirmed cases starting between the 17th and 20th of September.	Observations: Fond Du Lac, Outagamie and Winnebago's daily confirmed cases roughly doubled  12 days after the rally, and continued to rise.

Mankato, Blue Earth County, MN 8/17/2020	Old Forge, Lakawanna County, PA 8/20/2020	Rockingham, Londonderry, NH 8/28/2020
Observations: Blue Earth sees a rise in cases 10 days after the rally. Brown sees a rise in cases 26 days after the rally. Faribault sees a rise in cases around 12-14 days after the rally. Le Sueur sees a rise in cases 3-4 days after the rally that rises to a peak after 11-12 days after the rally and then falls. We assume this not likely to be associated with the rally. Martin sees a rise in cases 12 days after the rally with a peak at 17 days, followed by a dip and then a larger rise in cases. Nicollet sees no apparent rise in cases. Waseca cases are on a rising slope when the rally occurs, this plateaus after 4 days until day 17 when it again rises Watonwan is very variable so no conclusions are made	Observations: There are significant rises in the number of cases in the 2-14 days after the event on 8/20/20. In particular for Lackawana county 10 days after the rally. There is a rise for Susquehanna county starting just before the rally. Also, Wayne county sees a rise about 14 days after the rally. On the other hand, Luzerne county sees a similar rise two weeks before the rally.	Observations: There is a rise in confirmed cases for all counties, 5-14 days following the rally.

Also see

• https://time.com/5865890/oklahoma-covid-19-trump-tulsa-rally/
• https://www.axios.com/trump-rally-fined-violating-covid-guidelines-1566236b-0177-4407-b139-a7f69c11db66.html
• https://thenevadaindependent.com/article/nevada-health-officials-predict-uptick-in-covid-19-cases-following-labor-day-weekend-crowds-trump-rallie