While Pima County lacks the vaccine supply to vaccinate enough of the population to reach herd immunity, COVID-19 cases are decreasing across the state. Health experts warn, however, that continued mitigation is needed to maintain the downward trend.

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, the week ending Jan. 31 saw a 31% decrease in total COVID-19 cases from the week prior.

In Pima County, coronavirus cases saw a 27% decrease the week ending Jan. 17 from the week before, Gerald reports.

Data from the Pima County Health Department reflects a similar trend. The first week of January saw Pima County’s highest weekly number of COVID-19 cases at 8,860, while the following week dropped to 7,052 and the third week to 5,260. Week four reported 2,916 cases, but data from the last 4-7 days are still trickling in.

“I'm cautiously optimistic. So we have 130,000 plus vaccinated. We have over 103,000 cases, which confers some immunity, at least for that particular 90 days. We do seem to be seeing a decrease in our cases day by day,” said Dr. Theresa Cullen, Pima County’s health department director. “Overall, if we look at what we call the epi curve, we do see that epi curve seems to have hit its peak and is coming down. That is also consistent with what we're seeing with our hospitalizations. We have more ICU bed availability than we have had for the past eight weeks.”

However, Cullen said the county’s test positivity of 12.5% is still high, and while COVID-19 testing has decreased, it hasn’t corresponded with a decreased positivity rate.

“That means that we still have a lot of COVID transmission occurring in the county,” Cullen said.

While the week ending Jan. 17 remains Arizona’s deadliest at 913 reported COVID-19 deaths, Gerald said deaths will remain high for the next four to eight weeks.

The county health department reports 134 COVID-19 deaths for January’s first week, 125 for the second, 85 for the third and six deaths for the last week of the month.

Across the state, COVID-19 hospitalizations dropped 20% from the week before Feb. 5, while ICU bed usage by coronavirus patients dropped 14%, according to Gerald’s report.

To maintain the reduced spread, Gerald said continued mitigation against COVID-19 is essential.

“One pressing challenge moving forward will be ‘holding the line’ on our public health mitigation practices in the face of improving conditions. For example, absolute levels of transmission and test positivity remain 3-4X higher than recommended for in-person instructional activities,” Gerald said. “Resumption of high-risk activities before absolute levels further subside would be akin to jumping out of your exit-row seat at 10,000 feet when the pilot announces his initial descent into the airport. It matters little whether you jump out on the way up or way down; it’s going to hurt either way.”