PHOENIX >> Most counties in Arizona, including the state’s most populous one, were cleared today to transition their schools to some form of in-person learning after recent coronavirus data showed improvements.

The state Department of Health Services announced that eight of Arizona’s 15 counties now meet the benchmarks required to do a hybrid of remote and in-person instruction if they choose to. They include Maricopa and Pima counties. Meanwhile, Greenlee and La Paz counties, which are more rural, got the green light to switch to full-time, in-person classes.

State Superintendent of Public Instruction Kathy Hoffman, however, urged caution as school districts consider whether to make the switch.

“As we saw at the end of spring and throughout the summer, COVID-19 can spread very quickly when we fail to adhere to essential mitigation strategies like wearing masks and practicing social distancing,” Hoffman said in a statement.

Mesa Public Schools, the state’s largest school district in terms of student body, said today that administrators now hoped to start hybrid learning beginning Sept. 14. But the district will make a final decision after seeing next week’s data.

Under an executive order issued by Gov. Doug Ducey in June, there are three key criteria that counties need to fulfill for schools to offer hybrid instruction. A county must have a decline in new cases or a rate of less than 100 new cases per 100,000 people in a two-week period. In that same time frame, a county must also show a test positivity rate below 7% and hospital visits for COVID-19-like illness are below 10%.

Greenlee and La Paz counties demonstrated figures low enough to be categorized as having minimal community spread.

Arizona health officials today reported 1,091 additional confirmed COVID-19 cases with 65 additional deaths, increasing the state’s totals to 203,953 cases and 5,130 deaths.

It was the first time in three weeks that the Department of Health Services reported over 1,000 additional cases. The agency reported 1,351 on Aug. 13.

Arizona was a national hot spot in June and July, with cases and deaths trending downward since.

Seven-day rolling averages for daily new cases and daily deaths reported statewide continued to decrease through Wednesday, according to Johns Hopkins University data analyzed by the Associated Press.

The rolling average of new cases went from 873 on Aug. 19 to 486 on Wednesday, while the rolling average of daily deaths dropped from 41 to 28 during the same period.

The number of infections is thought to be far higher because many people have not been tested, and studies suggest people can be infected with the virus without feeling sick.

For most people, the new coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death.

In other developments, the University of Arizona in Tucson is ramping up testing and monitoring of students. University President Robert Robbins said today the school will increase COVID-19 tests to about 5,000 weekly. The school has also hired unarmed, private security to warn anyone seen violating health and safety guidelines.

“A small number who do not follow the guidelines and adhere to directives can spoil it for everyone,” Robbins said during a news briefing. “It’s actually endangering people’s lives.”

The university reported Wednesday 126 new positive cases, the highest daily number to date, Robbins said. Since July 31, the school has confirmed 397 cases. The school’s designated “isolation dorms” currently contain 54 infected students. Instruction at the school has been remote except for essential lab classes.