Arizona is seeing an upswing in the number of COVID cases in the state. As best as we can tell using the back calculation method, the new uptrend for cases began with a change in the rate of incidence of exposure to the viral infection approximately between 8 October and 11 October 2021. The following chart shows the latest trends for the number of COVID cases, hospital admissions, and deaths indexed to the approximate date of when those infected were initially exposed to the variants of the SARS-CoV-2 coronavirus being transmitted within the state.
The state's detailed data for hospital admissions and deaths is still as yet too incomplete to tell if they will follow the pattern for the uptrend in cases. The impact of the COVID vaccines combined with improved treatments however has clearly made COVID less serious than it was during 2020.
The period of 8 October through 11 October 2021 was characterized by what might be considered several mass exposure events within the state. Here's a sampling of sporting events that drew thousands in attendance to each:
- Suns run open practice with thousands in attendance; Booker talks NBA 75 shoot
- Arizona falls to UCLA, extending losing skid to 17 straight; QB Jordan McCloud injured
- ASU football rides hot offensive start, take down Stanford
- Cardinals earn forgettable win over 49ers to stay atop NFC West
That's just the sporting events in the state during that period, without including things like tailgate parties or other social gatherings that could constitute significant exposure events.
We were curious to see if Arizona's COVID data could provide more insight into where cases are now arising in the state. The following image is a snapshot of COVID cases by ZIP code in the state, where the darker red the color, the greater the number of cases in the last month.
The map is fascinating because with a few exceptions it shows the higher levels of new COVID cases in ZIP codes are taking place in regions that might be considered to be the suburbs and exurbs of the Phoenix and Tucson metropolitan areas. Here's the short list of the ZIP codes that became the darkest red during the past month:
- 85706: 793 cases
- 85142: 792 cases
- 85338: 792 cases
- 85345: 771 cases
- 85326: 763 cases
- 85122: 717 cases
- 85009: 713 cases
It would be interesting to see if those testing positive for COVID-19 infections in these ZIP codes share any common characteristics. Arizona's public data for infections at this level however doesn't provide enough detail to tell.
Previously on Political Calculations
Here is our previous coverage of Arizona's experience with the coronavirus pandemic, presented in reverse chronological order.
- Arizona's COVID Hospital Admissions Unexpectedly Plunge
- All Indicators Confirm COVID Third Wave Receding in Arizona
- Arizona's Third COVID Wave Peaks and Begins to Recede
- Arizona COVID Cases Rising in Third Wave
- Arizona COVID Cases on Slow Uptrend in Summer 2021
- Increase in Arizona COVID Cases from Border Migration Crisis Stabilizing
- COVID-19 and the 2021 Border Migration Crisis in Arizona
- Improving COVID Trends Bottom and Flatline in Arizona
- Surge of Migrants, Lifting of Business Capacity Limits Change Arizona COVID Trends
- COVID-19 in Retreat in Arizona With Vaccines Gaining Traction
- The Ebb and Flow of COVID-19 in Arizona's ICUs
- Arizona's Plunging COVID-19 Caseloads and the Vaccines
- Arizona Enters Downward Trend for COVID-19 After Second Peak
- Arizona Passes Second COVID-19 Peak
- A Tale of Two States and the Coronavirus
- COVID-19 Questions, Answers, and Lessons Learned from Arizona
- The Deadly Intersection of Anti-Police Protests and COVID-19
- 2020 Campaign Events Drive Surge in Arizona COVID Cases
- 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
Political Calculations has been following Arizona's experience with the coronavirus experience from almost the beginning, because the state makes its high quality data publicly available. Specifically, the state's Departent of Health Services reports the number of cases by date of test sample collection, the number of hospitalizations by date of hospital admission, and the number of deaths by date recorded on death certificates.
This data, combined with what we know of the typical time it takes to progress to each of these milestones, makes it possible to track the state's daily rate of incidence of initial exposure to the variants of the SARS-CoV-2 coronavirus using back calculation methods. Links to that data and information about how the back calculation method works are presented below:
Arizona Department of Health Services. COVID-19 Data Dashboard: Vaccine Administration. [Online Database]. Accessed 15 November 2021.
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]. 10 September 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.