01 October 2021

All Indicators Confirm COVID Third Wave Receding in Arizona

We've been following Arizona's experience with the coronavirus experience since the state makes its high quality data publicly available. That data makes it relatively easy to identify turning points in the rate of incidence for exposure to the SARS-CoV-2 coronavirus within the state.

The state's data as of 1 October 2021 confirms the rate of incidence of new COVID infections in its third wave peaked during the week of 15 August 2021 through 21 August 2021. All indicators, including cases, hospitalizations, and deaths all point to that timing as the data is now complete enough to make that confirmation:

Arizona's Coronavirus Pandemic Experience, 15 March 2020 - 15 September 2021, Snapshot on 1 October 2021

The timing is notable in that neither the state nor the federal government adopted any new interventions, such as mask-wearing policies during that period, making it different from earlier periods where changes in trend coincided with such interventions.

Since peaking, the number of new cases has fallen slowly, though new hospital admissions have fallen more steeply. The data for deaths lags behind these two other indicators, so it will be interesting to see which trajectory of these two other data series they more closely follow in the weeks ahead.

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 1 October 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.