Arizona COVID Cases On Slow Uptrend In Summer 2021

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Posted: Jul 15, 2021 1:11 PM
Arizona COVID Cases On Slow Uptrend In Summer 2021

Source: AP Photo/Tsafrir Abayov

It has been nearly two months since we focused on Arizona's experience during the coronavirus pandemic. When we last checked, it appeared Arizona's level of COVID cases following the surge of uncontrolled immigrant crossings into the state was stabilizing.

That pattern held through the end of May 2021. However, beginning in the first week of June 2021, Arizona has experienced a slow upward trend in cases. That new trend can be seen in the following chart tracking the 7-day moving averages of the state's COVID cases and new hospital admissions. Presented in logarithmic scale, the figures for each data series has been aligned with respect to the approximate date of initial exposure to the SARS-CoV-2 coronavirus variants infecting those who have tested positive for COVID-19.


At this time, the data for COVID deaths is as yet too incomplete to confirm the change in trend across all three data series.

The change in trend appears to roughly coincide with the Phoenix Suns' first trip to the NBA playoffs in more than a decade, which prompted large crowd gatherings and celebrations after the team beat the Los Angeles Lakers in the first round of the playoffs in the first week of June 2021. The team has continued its success, beating both the Denver Nuggets and the Los Angeles Clippers, and is now playing the Milwaukee Bucks for the championship in the NBA finals.

The situation parallels the change in trend we observed in California after the Los Angeles Dodgers won the World Series. The main difference is that Arizona's current upward trend is rising at a much slower rate. We think that difference is attributable to the Operation Warp Speed coronavirus vaccines, which have been successfully deployed to half the state's population, especially the state's senior population, which has reduced the incidence of COVID-related hospitalizations and deaths.

The state is also seeing an uptrend in COVID ICU cases that has really picked up in late June 2021.


The timing of the increase in COVID ICU bed usage is delayed about two weeks behind what we would expect for a major change in the rate of incidence beginning in the first week of June 2021. We think this delay may be similar to what Arizona experienced following the Black Lives Matter protests and riots in late May and early June 2020 because of the age demographics of the participants. Then as now, younger individuals less likely to require hospitalization were infected in relatively larger numbers, which then spread to the older individuals they came in contact with following the event. The older individuals were the ones who drove up hospital admissions and ICU bed usage after they became sick, roughly two weeks afterward.

Exit question: Will any enterprising attorneys make the connection and hold the NBA accountable? They don't seem to have figured out the BLM protest connection in Arizona's May-June 2020 surge in COVID cases....

Previously on Political Calculations

Here is our previous coverage of Arizona's experience with the coronavirus pandemic, presented in reverse chronological order.

References

We've continued following Arizona's experience during the coronavirus pandemic because the state's Department of Health Services makes detailed, high quality time series data available, which makes it easy to apply the back calculation method to identify the timing and events that caused changes in the state's COVID-19 trends. This section links that that resource and many of the others we've found useful throughout the coronavirus pandemic.

Arizona Department of Health Services. COVID-19 Data Dashboard: Vaccine Administration. [Online Database]. Accessed 25 April 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]. Updated 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.