COVID-19 cases have decreased in Arizona for the second week in a row, but the state remains the nation’s highest for transmission of the virus.

CDC data shows Arizona’s average transmission rate is at 75 daily cases per 100,000  population. The state has held the first or second spot through most of January.

The week ending Jan. 24 showed an 18% decrease in coronavirus cases from the previous week prior, according to the latest report by Dr. Joe Gerald, a University of Arizona professor who creates weekly coronavirus epidemiology reports based on Arizona Department of Health Services data.

“This week saw another meaningful decline in COVID-19 cases which now clearly represents a sustained, real decrease in viral transmission,” Gerald wrote in this week’s report. “This decline is accompanied by reductions in hospital and ICU occupancy. Reductions in mortality should quickly follow. While this reprieve is welcomed, the absolute level of [coronavirus] transmission remains exceptionally high.”

The week ending Jan. 10 remains the state’s deadliest with 889 COVID-19 deaths recorded so far. Gerald predicts deaths will remain “exceptionally high” for the next four to six weeks.

Pima County’s outlook

In Pima County, positive cases from the week ending Jan. 17 decreased by 26% since the previous week, Gerald’s report says.

The first week of January saw Pima County’s highest weekly number of COVID-19 cases at 8,814, while the following week dropped to 6,971 and the third week to 4,986, according to the latest Pima County Health Department report. Data from the last 4-7 days are still trickling in, however.

the week ending Jan. 24 shows an 18% decrease in coronavirus cases from the week prior.

Coronavirus deaths in January’s first week tallied 126, the second week 116 and the third week 55, the county reports.

According to Pima County’s Chief Medical Officer Dr. Francisco Garcia, three key indicators tracking the spread of COVID-19 are decreasing throughout the county: cases per 100,000 individuals, percent positivity and hospital visits for COVID-like illness.

This leads him to believe the downward trend in coronavirus cases will sustain.

“All of those are moving in the right direction. If it was going to be short-lived I would expect some of those to not be trending in the same direction,” Garcia said.

However, the trend won’t continue without widespread adherence to virus mitigation practices like mask-wearing, social distancing and frequent sanitization.

“I think we could sustain it if we don't get sloppy again,” Garcia said. “If we continue to do the common sense kinds of mitigation measures that we have tried to reinforce as much as possible, I think we will mitigate against it.”

COVID-19 mutations could quicken transmission

Today, Arizona has reported 762,145 total COVID-19 cases and 13,124 deaths, while Pima County has reported 101,961 cases and 1,740 deaths, according to ADHS Data.

Cases could transmit even faster with the arrival of more contagious coronavirus variants from the UK, South Africa and Brazil in the U.S.

The UK variant has been identified in Arizona after at least three test samples came back positive for it, the ADHS announced Friday.

The CDC says while studies are still underway, they suggest that the current COVID-19 vaccines will defend against the mutations.

In Arizona, coronavirus vaccinations have been in the works since mid-December, but only 1.3% of Arizona’s residents have been fully vaccinated with the two doses required to be considered fully immunized, according to Bloomberg’s COVID-19 tracker. In Pima County, vaccine availability is outstripping the demand for them.

Hospitals are still overwhelmed

As of Jan. 29, COVID-19 patients occupying hospital beds decreased 14% from the previous week, while ICU bed usage decreased by 6%, according to Gerald.

According to Pima County Health Department data, the first week of January had 434 COVID-19 hospitalizations, the second week 338 and the third week 218.

However, a memo from Pima County Administrator Chuck Huckelberry reports hospitals’ capacity still remains critical.

On Jan. 29, ICU bed availability was at 5% with only 19 beds available. According to the memo, capacity has remained below 10% for 80 days.

The county’s medical surge beds have remained under 10% capacity for 87 days, with 121 beds available as of last Friday, the memo says.

COVID-19 patients accounted for 45% of total ICU bed usage, and 116 coronavirus patients were on ventilators, representing 55% of total ventilator usage in the county.

While data tracking the spread of COVID-19 across the state shows promising downward trends, the pandemic is still challenging hospitals’ ability to provide care, and the slight reprieve in the state comes relative to the sustained widespread transmission of the virus.

“While conditions are improving, Arizona remains in a public health crisis where access to critical care services is limited due to shortages of space, personnel and critical supplies,” Gerald said. “These conditions will persist into early February before easing. Additional mitigation efforts could further slow viral transmission, more quickly reduce hospital burden, and allow additional time to vaccinate those at greatest risk.”