Since we last looked at Arizona's experience with COVID-19, the number of coronavirus-related cases, hospital admissions, ICU bed usage, and deaths has continued to rise at an increased pace.

Currently, the available data does not yet show any change related to social mixing during the Thanksgiving holiday. But the data does continue to show the impact of social mixing the back calculation method indicates coincided with political campaign events that occurred within Arizona during the period from Friday, 23 October 2020 through Sunday 25 October 2020.

Hospital Admissions

Arizona's new hospital admissions datacontinues to provide the some of the clearest data for determining when events occurred to change the incidence of exposure to the SARS-CoV-2 coronavirus. Our first chart shows the available data from 3 March 2020 through 30 November 2020, with the rolling 7-day average shown through 23 November 2020.

In the chart, we've added a linear trend line to indicate the trajectory that new hospital admissions were taken after what we've identified as Event H, which corresponds to when most high exposure-risk businesses reopened in the state. The trajectory of new hospital admissions (shown as the heavy purple line for the 7-day rolling average of this data) turns upward after the expected 11-13 day lag following the political campaign events that centered around the 24 October 2020 "National Vote Early Day" events in the state some two-and-a-half weeks before election day.

ICU Bed Usage

ICU bed usage data in Arizona has nearly the same lag from initial exposure to hospitalization, but is more complete because there is a limited supply of such facilities making it easier to track serious COVID-19 hospitalizations in real time. Our second chart shows the available data for ICU bed usage in Arizona from 3 March 2020 through 30 November 2020, with the rolling 7-day average shown through 30 November 2020.

While this data is current through 30 November 2020, that is still several days too early to tell what impact the Thanksgiving holiday had on the incidence of coronavirus infections within Arizona. We anticipate that if the holiday had an effect on the current trend for hospitalizations, it will start showing up in this data in the period from 4 through 7 December 2020.

Newly Confirmed Cases

Unlike many states, Arizona makes its data on confirmed cases by date of test sample collection available. While this data indicates the shortest lag between virus exposure to positive COVID-19 test results, it takes several weeks for a given day's result to become relatively finalized, although it is mostly complete after two weeks.

Our third chart shows the available data for newly confirmed COVID-9 cases in Arizona from 3 March 2020 through 30 November 2020, with the rolling 7-day average shown through 23 November 2020.

Like the new hospital admissions chart, this chart confirms the increased pace of new cases being recorded some nine to eleven days after the political campaign events of 23-25 October 2020.

At the same time, the chart confirms the rolling 7-day average number of newly confirmed cases is nearing the peak of what was recorded during Arizona's first surge in cases during in the early summer of 2020.

Deaths

The data for coronavirus-related deaths in Arizona is reported with the greatest lag, but it is now starting to confirm the effect of the 23-25 October 2020 political campaign events had on changing the incidence of COVID-19 infections. Our fourth and final chart shows the available data for deaths attributed to COVID-19 in Arizona from 3 March 2020 through 30 November 2020, with the rolling 7-day average shown through 19 November 2020.

Using dates for which all data is relatively finalized, we can compare 15 June 2020 with 6 November 2020. For both dates, the rolling 7-day average for the number of newly confirmed cases in Arizona first rose above 2,000 cases per day after having previously been below that level. On 15 June 2020, 7-day rolling average for COVID-19 deaths reached 30 per day in Arizona, but on 6 November 2020, the equivalent figure was 17 per day.

That change suggests the SARS-CoV-2 coronavirus has become less deadly. We think that difference is most likely attributable to improvements in available medical treatment since the summer.

Since we won't start seeing the impact of Thanksgiving in the data for another week, we'll close this edition of our series on that bit of good news.

Previously on Political Calculations

Here's our previous Arizona coronavirus coverage, with a sampling of some of our other COVID analysis!

• Arizona Arrives at Critical Junction for Coronavirus Cases
• Arizona To Soon Reach A Critical Junction For COVID-19
• Getting More Than Care from Arizona's COVID ICU Beds
• Arizona's Decentralized Approach to Beating COVID
• Going Back to School with COVID-19
• Arizona Turns Second Corner Toward Crushing Coronavirus
• Arizona's Coronavirus Crest in Rear View Mirror
• The Coronavirus Turns a Corner in Arizona
• A Delayed First Wave Crests in the U.S. and a Second COVID-19 Wave Arrives
• The Coronavirus in Arizona
• A Closer Look at COVID-19 Deaths in Arizona
• The New Epicenter of COVID-19 in the U.S.
• How Long Does a Serious COVID Infection Typically Last?
• How Deadly is the COVID-19 Coronavirus?
• Governor Cuomo and the Coronavirus Models
• How Do False Test Outcomes Affect Estimates of the True Incidence of Coronavirus Infections?
• How Fast Could China's Coronavirus Spread?

References

Arizona Department of Health Services. COVID-19 Data Dashboard. [Online Application/Database].

Maricopa County Coronavirus Disease (COVID-19). COVID-19 Data Archive. Maricopa County Daily Data Reports. [PDF Document Directory, Daily Dashboard].

Stephen A. Lauer, Kyra H. Grantz, Qifang Bi, Forrest K. Jones, Qulu Zheng, Hannah R. Meredith, Andrew S. Azman, Nicholas G. Reich, Justin Lessler. The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Annals of Internal Medicine, 5 May 2020. https://doi.org/10.7326/M20-0504.

U.S. Centers for Disease Control and Prevention. COVID-19 Pandemic Planning Scenarios. [PDF Document]. Updated 10 September 2020.

COVID Tracking Project. Most Recent Data. [Online Database]. Accessed 10 November 2020.

More or Less: Behind the Stats. Ethnic minority deaths, climate change and lockdown. Interview with Kit Yates discussing back calculation. BBC Radio 4. [Podcast: 8:18 to 14:07]. 29 April 2020.