Figure 2a shows the sharp decline in transmission among children (dotted) slowing a bit this past week. The smallest gains are observed among the elderly (solid). We now have even stronger evidence supporting mask mandates in K – 12 schools. According to ASU, MCDPH, and PCHD researchers, Arizona schools without a mask mandate have 3.5 times the odds of having a school outbreak (95%CI 1.8 – 6.9). Clearly, mask mandates are helping to slow transmission among school-age children 5 – 19 years (Figure 2b). A judge presiding over the challenge to Arizona’s prohibition of school mask mandates intends to rule before the September 29^th date the law will take effect.

Comparing school reopening this year (in-person) with last year (virtual), levels of community transmission are 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 ongoing this time last year (orange bars, ages 15 – 24). Transmission on campus is not an outlier this year which is consistent with the data reported on the UA COVID-19 Dashboard which indicates fewer reported cases on campus this year than last.

Over the past month, the trajectory of the current outbreak and that of the winter 2020/2021 outbreak have meaningfully diverged (Figure 2d). We are now experiencing a more permanent shift away from last year’s trajectory. Nevertheless, improvements from the peak are considerably slower this time than either of the last two peaks meaning the size (volume) of this wave could eventually exceed that of the summer 2020 wave.

Test positivity among those undergoing traditional nasopharyngeal testing remains unexpectedly high at 21% (Figure 3). This level of positivity indicates that testing is woefully inadequate for public health practice and that many cases are going undiagnosed. It appears that the disruption in testing associated with Labor Day is passing. 

As of September 22^nd, 1893 (22%) of Arizona’s 8773 general ward beds were occupied by COVID-19 patients, an 8% decrease from last week’s 2050 occupied beds (Figure 4 and Figure 5 Panel A). Another 683 (8%) beds remained available for use. The number of available beds is fewer than last week’s 695 beds.

As of September 22^nd, 539 (30%) of Arizona’s 1772 ICU beds were occupied by COVID-19 patients, a 5% decrease from last week’s 565 occupied beds (Figure 4 and Figure 5 Panel B). An additional 132 (7%) ICU beds remained available for use, fewer than last week’s 143 beds.

As a lagging indicator, hospital COVID-19 occupancy is now declining as expected in the general ward and ICU.

Arizona hospital occupancy remains above seasonal levels. Safety margins, as measured by excess available beds, remain quite low (Figure 6). Available excess capacity is nearly as low as it was at the worst of the winter 2020/2021 surge. Because occupancy is not improving in response to declining community transmission, hospitals should be prepared for >20% ward occupancy and >25% ICU occupancy for another week or two. Even if you are vaccinated, the tail of this COVID-19 surge will still impact your access to healthcare services should you become ill.

Arizona has experienced >200 COVID-19 deaths per week the past 3 weeks (Figure 7). The week ending September 5th has so far recorded 280 deaths with the week ending September 12th close behind with 218 recorded deaths. In a sobering reversal, 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 September 19th, 1678 Pima County residents were diagnosed with COVID-19 a 2% decline from last week’s initial tally (Figure 8). This marks the 4th week of declining case counts although the decline is more modest than the state trend.

New cases are being diagnosed at a rate of 160 cases per 100K residents per week and is declining by 5 cases per 100K residents per week. Trends across the various age groups appear in Figure 9.