SANTA ANA, Calif. (CNS) — Orange County's COVID-19 cases and hospitalization rates continue to mount as officials brace for a Thanksgiving-fueled surge.

The county's Health Care Agency reported 1,199 newly diagnosed cases of COVID-19 on Wednesday, raising the cumulative total to 73,152. The HCA also logged three more fatalities, hiking the death toll to 1,559.

The number of county residents hospitalized with the virus increased from 463 on Tuesday to 479, with the number of patients in intensive care dropping from 116 to 115, according to the OCHCA.

The change in the three-day average of hospitalized patients inched up from 26.8% to 27.1%. The county has 30% of its intensive care unit beds and 64% of its ventilators available.

In the state's tiered system, which is updated on Tuesdays, the county's adjusted daily case rate per 100,000 residents jumped from 10.8 to 17.2 and the positivity rate swelled from 4.6% to 6.8%.

The positivity rate fits in the red tier of the state's four-tier reopening roadmap, but the daily case rate per 100,000 is well past the 8% threshold for the most-restrictive purple tier.

The case rate per 100,000 is adjusted based on the level of testing a county does, Orange County CEO Frank Kim said. The unadjusted case rate per 100,000 is 20.2, which is similar to the 21.5 unadjusted rate in San Diego County, he noted.

Kim said he was "very concerned" about the rise in cases and hospitalizations.

"And even though the various hospital (executives) I have conversations with seem more confident today than they were early on in the disease in how to treat it, I'm not taking any of it lightly," Kim said. "Any rise in hospitalizations and ICU rates is a significant concern for our community."

County officials are imploring residents to avoid gatherings for Thanksgiving and to stay at home as much as possible, but if they insist on attending get-togethers they should be tested before and after.

Officials recommend waiting at least two days after an event or gathering to get tested because the infection might not be detected right away.

Andrew Noymer, a UC Irvine associate professor of population health and disease prevention, warned of a grim winter.

"I'm very apprehensive of the trends we're going to see after Thanksgiving," Noymer told City News Service. "People don't appreciate that we were recording deaths from the summer wave through October."

Noymer predicted more cases than the July peak.

"But this is not just going to be like another July and go away," Noymer said. "I think it's going to get worse."

The last time hospitalization rates were this high was Aug. 10, Noymer said.

"At the end of next week we'll be back to July (levels)," Noymer said. "And will it crest like in July or keep getting worse. There's reasons to believe we could just keep getting worse."

Noymer said that's mainly because the colder weather is pushing people into more indoor activities and some students are still attending classes in classrooms.

The worst day for COVID-19 hospitalizations in Orange County was July 14, when there were 722 patients.

Kim, who is recovering from COVID-19, said it is the most difficult illness he has had to cope with, but he was feeling better on Wednesday.

Kim said he was optimistic vaccines are on the way and are scheduled to arrive by year's end. Hospital systems will get the vaccines directly and individual hospitals will receive doses from the county, Kim said.

Frontline health care workers will be among the first to receive vaccinations, along with people with underlying health conditions that make them especially vulnerable to the disease.

The hope is that increased testing and awareness of infections will encourage more quarantining and isolation and other social distancing practices that help curb the spread of the virus, Kim said.

The county's tests per 100,000 stands at 354.1, outstripping the county's goals for testing at this point, he said.

Kim said the county is focusing on encouraging testing. The number of tests conducted in the county is 1,385,195, including 15,084 reported Wednesday. There have been 58,608 documented recoveries.

An air traffic controller at John Wayne Airport tested positive for COVID-19, but Kim said it has not affected air safety or flight schedules.

Much of the airport's air traffic control operations are being run out of San Diego, Kim said.

"There are no issues with safety and they're just dealing with the same protocols we're all dealing with when you get someone who is positive -- you have to isolate everyone they've been in contact with," Kim said.