LOS ANGELES (CNS) — COVID-19 patients continued flooding Los Angeles County hospitals Thursday, mirroring a regional and statewide surge that threatens to overwhelm emergency departments and intensive-care units.

The dramatic coronavirus surge — which on Wednesday saw Los Angeles County set daily records for new cases and deaths and overall hospitalizations — has health officials continuing their plea for residents to heed warnings to avoid gatherings and continue social distancing and mask-wearing.

"Based on the science of transmission of COVID-19, the devastation we are experiencing now is due to people who were unknowingly infected with the virus being in close or direct contact with another person or group long enough to infect them," county Health Officer Dr. Muntu Davis said. "It may have occurred at work or when they traveled or visited with people outside their homes who they don't live with over the holidays, either here in the county or in another county or another state or another country.

"The science of COVID-19 transmission also indicates that the transmission occurs more easily in crowded spaces with many people nearby, close-contact settings especially where people have conversations very near each other, and in confined spaces or closed spaces with poor ventilation," he said. "The risk of COVID-19 spreading is higher in places where these three conditions overlap."

The impact of the virus surge on the emergency medical system was made clear Thursday morning, when the state announced that the 11-county Southern California region had formally reached zero capacity in intensive-care units. The designation does not mean there are no beds available, since the state adjusts the capacity figure based on the ratio of COVID patients occupying ICU space.

According to the Los Angeles County Department of Health Services, as of Thursday there were only 716 staffed and available beds available at the 70 "911-receiving" hospitals that have emergency departments. Only 92 of those available beds were ICU beds, down from an estimated 102 on Wednesday. County hospitals have an overall licensed capacity of about 2,500 ICU beds, and hospitals have increased staffing to operate roughly that number over the past week.

Last week, county hospitals operated an overall average of about 10,360 non-ICU beds per day, based on physical space and available staffing. Overall, hospitals are licensed to operate about 17,000 non-ICU beds, but that number is restricted by the availability of staffing to treat patients.

The county on Thursday reported a total of 4,864 COVID patients in hospitals, up about 200 from the previous day and the highest level of the pandemic. Roughly 20% of those people were in ICU beds, or about 973. The state's website earlier Thursday listed the county's COVID hospitalization number at 5,100.

"Our hospitals are under siege, and our model shows no end in sight," county DHS director Dr. Christina Ghaly said Wednesday, adding, "The worst is still before us."

Ghaly said hospitals were averaging about 600 coronavirus admissions per day, up from around 500 last week. Based on current trends, hospitals could be admitting anywhere from 750 to 1,350 new COVID admissions per day by the end of December, she said.

On Thursday, the county Department of Public Health reported 102 additional coronavirus fatalities, although four of those were actually announced Wednesday by health officials in Long Beach. Long Beach reported another four deaths Thursday afternoon, while Pasadena announced three more. The new fatalities gave the county an overall total of 8,671 deaths since the start of the pandemic.

Public Health Director Barbara Ferrer said average daily deaths from COVID-19 in the county have spiked up 267% since Nov. 9, reaching 44 per day as of last week, and likely even higher this week given the recent rising death figures. Ferrer said that equates to two people in the county dying from COVID- 19 every hour.

Another 14,418 COVID infections were confirmed in the county Thursday. Long Beach health officials reported another 993 cases Thursday afternoon, while Pasadena health officials announced a daily record of 201 new infections. The new cases lifted the countywide cumulative total to 581,519.

County officials said the local transmission rate for COVID-19 — the average number of people each COVID-positive person infects with the virus — is now 1.2, up from 1.16 a week ago. Anytime the rate is above 1, case numbers are projected to grow.

The county also estimates that one of every 80 residents not hospitalized or in quarantine/isolation is infected with the virus, likely without knowing it or showing any symptoms, yet still capable of infecting others.

Since new infections, hospitalizations, and deaths generally reflect actions people took two weeks ago — based on the incubation period of the virus — health officials said the numbers will continue to get worse in the coming weeks. They again implored people to return to adherence to health protocols ahead of the holidays to avoid another surge on top of a surge.

"Really the thing to focus on right now is that each and every one of us and our family and friends and our colleagues and coworkers do what's needed to slow this infection from spreading as rapidly and widely as it has," Davis said. "There's just too much risk in terms of the numbers of cases that are in the community that are being diagnosed each day. We're already seeing the impact it's having on our health care system as well as the number of deaths that are being reported."

Although vaccines are starting to be administered in Los Angeles County and across the country, officials noted that it will not quell the current surge of cases and won't be widely available to the general public for months.

The Southern California region — which covers Los Angeles, Orange, Riverside, San Diego, Imperial, Inyo, Mono, San Bernardino, San Luis Obispo, Santa Barbara, and Ventura counties — is under a state-imposed regional stay-at-home order that bars gatherings of people from different households and forced the closure of many businesses, while restricting capacity at others.

Schools with waivers can remain open, along with "critical infrastructure" and retail stores, which will be limited to 20% of capacity. Restaurants are restricted to takeout and delivery service only. Hotels are allowed to open "for critical infrastructure support only," while churches would be restricted to outdoor only services. Entertainment production — including professional sports — would be allowed to continue without live audiences.

The order will remain in effect until at least Dec. 28.