Figure 2a shows at least a temporary slowing of improvements among all groups except those 15 – 24 years of age. Worryingly, cases among those 65+ remain quite high despite high levels of vaccination among this group. ASU, MCDPH, and PCHD researchers recently provided strong evidence supporting K – 12 mask mandates; Arizona schools without mandates had 3.5 times the odds of a school outbreak (95%CI 1.8 – 6.9) as compared to those with a mandate. Similar conclusions were reported from county-level data in the US. Mask mandates remain an important component of our multi-dimensional response to slow transmission among school-age children (Figure 2b). The Arizona Supreme Court is expected hear oral arguments on the State’s prohibition of school mask mandates during the first week of November.

Comparing school reopening this year (in-person) with last year (virtual), levels of community transmission remains much higher this year than last, particularly among those <15 years (Figure 2c). Higher transmission among those 15 – 24 years associated with university re-openings was almost resolved this time last year (orange bars, ages 15 – 24). Campus outbreaks have been less of an issue this year; after a modest outbreak in September, cases reported on the UA COVID-19 Dashboard have been declining in October on base of steady testing, about 1000 per day. Test positivity is <1% overall and generally <5% at campus health.

Test positivity remains at 23% this week on a smaller base of tests (Figure 3). Testing is inadequate for public health practice and many cases are going undiagnosed. It is unclear how much at-home testing is supplanting clinical testing. Even so, test positivity in the clinical setting remains an important barometer of transmission.

As of October 6th, 1762 (20%) of Arizona’s 8770 general ward beds were occupied by COVID-19 patients, a 0% decrease from last week’s 1768 occupied beds (Figure 4 and Figure 5 Panel A). Another 669 (8%) beds remained available for use. The number of available ward beds is larger than last week’s 631 beds. Four-hundred seventy-seven (477, 27%) of Arizona’s 1774 ICU beds were occupied by COVID-19 patients, a 6% decrease from last week’s 510 occupied beds (Figure 4 and Figure 5 Panel B). An additional 126 (7%) ICU beds remained available for use, fewer than last week’s 138 beds. As a lagging indicator, hospital COVID-19 occupancy is now slowly declining in the general ward and ICU.

While peak occupancy with this third wave never reached levels seen in the prior two, the base of the wave has the potential to be broader. For example, the summer 2020 wave saw 57 days with combined ward and ICU occupancy >2000 patients. The current summer 2021 wave has so far seen 55 days with a combined occupancy >2000 patients. For comparison, the winter 2021 wave say 98 days above 2000 combined occupancy. This persistent base of COVID-19 occupancy will have important implications for hospitals as they attempt to meet the typically high season demands between October and February.

Arizona hospital occupancy remains far above seasonal levels. Safety margins, as measured by excess available beds, remain quite low (Figure 6). Because COVID-19 occupancy is improving slowly, hospitals should be prepared for >20% ward occupancy and >25% ICU occupancy for another week or two. The tail of this COVID- 19 surge continues to impact access to healthcare for anyone who becomes critically ill. Staffing shortages continue to impact care making capacity more constrained than these bed numbers reflect.

Arizona has been experiencing >200 COVID-19 deaths per week since August 22^nd. The week ending September 5th has so far seen 297 deaths (Figure 7). The week ending September 12th is close behind with 277 recorded deaths. It now almost certain that Arizona will reach 300 deaths per week for the weeks ending September 5^th and/or the week ending September 12^th with declines following soon thereafter.

For the week ending October 3rd, 1888 Pima County residents were diagnosed with COVID-19 an 11% increase from last week’s initial tally (Figure 8).

New cases are being diagnosed at a rate of 180 cases per 100K residents per week and this rate is increasing by 10 cases per 100K residents per week. Trends across the various age groups appear in Figure 9.