Arizona case rates remain “stuck” just above the threshold differentiating substantial and moderate risk owing to more transmissible variants (e.g., B.1.1.7) and normalization of business and social activities (e.g., EO 2021- 06). According to the CDC, vaccination rates continue to increase with 34% of Arizona’s adult population being fully vaccinated and another 15% having received one dose (49% with ≥1 dose). With 78% of the ≥65 population having received ≥1 dose, Arizona ranks in the bottom half of states.

New cases are now being diagnosed at a rate of 70 per 100K residents per week; this rate is slowly increasing. For reference, September 8^th marked the fall nadir between the summer and winter outbreaks at 38 cases per 100K residents per week. The post-holiday nadir was 53 cases per 100K residents on March 23, 2021. Unvaccinated Arizonans who are at risk of developing severe disease (e.g., age or comorbid conditions) or who simply wish to remain uninfected should continue to shelter as much as feasible because viral activity remains widespread.

Note: Data for this report was updated Friday, April 23 allowing 4 full days to adjudicate cases and keep week-over-week backfill <10%. This allows more interpretable comparisons and graphics. All comparisons are week-over-week changes.

Test positivity among those undergoing traditional nasopharyngeal PCR testing is slowly increasing; positivity was 10% this week (Figure 3). Positivity remains within the 5 – 10% window for optimal public health practice.

As of April 22nd, 594 (7%) of Arizona’s 8605 general ward beds were occupied by Covid-19 patients, a 4% increase from the previous week’s 569 occupied beds (Figure 4 and Figure 5 Panel A). Another 912 (11%) beds remained available for use. The number of available beds is lower than the previous week’s 1025 beds.

Covid-19 occupancy has dropped by 88% from its January 11^th peak of 5082 ward patients. The summer-fall nadir was 468 occupied beds on September 27th. The post- holiday nadir was 516 beds on April 4.

As of April 22nd, 187 (11%) of Arizona’s 1727 ICU beds were occupied with Covid-19 patients, a 21% increase from the prior week’s count of 154 patients (Figure 4 and Figure 5 Panel B). An additional 253 (15%) ICU beds remained available for use. This is similar to the prior week’s 254 available beds. ICU occupancy has fallen 84% from its January 11^th peak of 1183 occupied beds. The summer-fall nadir was 114 occupied beds on September 22^nd. The post-holiday nadir was 140 beds on April 7.

Arizona hospital occupancy remains above seasonal trends. Improvements in ward and ICU occupancy remain stalled at ≥85% occupancy (Figure 6). This indicates that medically necessary procedures that were previously postponed are being scheduled at higher than seasonal amounts to address the backlog of care. It will still take several more months to resolve. Occupancy will need to fall <70-75% before conditions will be back to “normal.” As capacity constraints are lessened, care practices should return to those prior to the outbreak ensuring all patients will receive optimal care. Hospitals will remain crowded through May before returning to pre-outbreak levels.

The week ending January 17th remains Arizona’s deadliest with 1089 deaths (Figure 7). With 193 deaths recorded, March 7^th may become the first week with <200 Covid-19 deaths since November. The summer – fall nadir was 51 deaths the week ending October 4^th.

For the week ending April 18th, 569 Pima County residents were diagnosed with Covid-19. This is a 7% decline from the 609 cases initially reported last week (Figure 8). Last week’s initial tally was upwardly revised by 2% (11 cases) to 620 cases.

New cases are being diagnosed at a rate of 55 cases per 100K residents per week and is slowly decreasing. For reference, October 9^th marked a nadir between the summer and winter outbreak at 46 cases per 100K residents per week. Case rates reached their lowest post-holiday level at 44 cases per 100K residents per week on March 20^th. Trends across the various age groups appear in Figure 9.