A record surge of COVID-19 cases in Chicago is putting an enormous strain on hospitals as the fast-spreading omicron variant sends an influx of mostly unvaccinated patients to emergency rooms, health experts and officials say.

And the situation could become even more perilous if the current wave of infections does not subside soon, health care workers say, especially for smaller hospitals located in areas of the city with low vaccination rates.

“This is probably the most strained or particularly awful it’s been throughout the pandemic,” said Dr. Sajal Tanna, an infectious disease specialist at Northwestern Memorial Hospital. “I guess there’s always room for it to get worse, but I hope it doesn’t, to be honest with you. I would say we’re stretched so thin right now.”

In a city of more than 2.7 million residents, there were only 120 intensive care beds available as of Saturday, according to Chicago’s COVID-19 dashboard. That means about 88% of beds for the most severely ill patients were in use. When it comes to non-intensive care beds, about 83% were occupied. Health officials are also seeing a rise in hospitalizations from children.

While omicron can lead to breakthrough infections in people who are fully vaccinated, the vast majority of COVID-19 patients are unvaccinated, said Dr. Robert Murphy, a professor of infectious disease at Northwestern University’s Feinberg School of Medicine and the executive director for the Institute of Global Health.

“The hospitals are not full of just everybody with COVID,” he said. “It’s 90% unvaccinated.”

The number of COVID-19 cases has skyrocketed in recent weeks to unprecedented levels due to the highly contagious omicraton variant, significantly dwarfing previous waves during the pandemic.

Chicago reported a seven-day average of 5,260 cases per day as of Friday, up 16% compared to the previous week. Deaths, which can lag behind cases, were averaging about 11 per day, down 12% from the last week.

The number of COVID-19 patients requiring hospital care averaged about 90 per day, according to the city’s surveillance program. However, Chicago’s pandemic tracking program was reporting delays in hospital data due to technical issues as of Sunday.

But with cases still rising, things could get worse before they get better, Murphy said.

“We haven’t reached the peak of the pandemic. We’re still going up,” he said. “This is expected to peak somewhere in the next one to two weeks. And then you will see, like they saw in South Africa in some of the European countries, you’ll start to see a decline, and it may actually be kind of a sharp decline.”

Some hospitals are already stretched to the limit, especially those located in underserved communities that have been particularly hit hard by the pandemic.

St. Bernard Hospital, located in Chicago’s Englewood neighborhood, did not have a single bed available in its intensive care unit on Sunday, according to a spokesman.

And it has not been alone. Holy Cross Hospital in the Chicago Lawn neighborhood and the West Side’s Mount Sinai Hospital did not have any ICU beds available as of Jan. 3, according to data from the U.S. Department of Health and Human Services.

St. Bernard, like many health care providers in the city and across the nation, also suffers from staff shortages as a result of workers testing positive for COVID-19, said spokesman David Rudd. As a result, the hospital has requested help from the state.

Adding to St. Bernard’s hardships: The hospital serves an area with one of the lowest vaccination rates in Chicago. The hospital is located in the city’s 60621 zip code, where just 44% of residents are fully vaccinated, according to city data that does not include information about booster doses.

Overall, about 69% of Chicago residents 5 years old and over were fully vaccinated as of Jan. 6.

Rudd said he was not aware of any patient being denied care because of a lack of ICU beds.

“Staff at the hospital are still providing safe care while hoping for a reprieve,” he said. “Everyone needs a break from the stresses of this virus.”

Some health experts say that while capacity is tight at hospitals, the situation is not an emergency at the moment. Ventilators, which are crucial to treating severely ill patients, remain widely available, with 62% not currently in use, according to city data.

But ventilators need staff. And that’s a problem if coronavirus infections sideline frontline health care workers.

“You need respiratory therapists and nurses and doctors and other hospital staff to run them to take care of this whole patient,” said Tanna, a doctor with Northwestern Memorial Hospital. “And I don’t know if there’s help out there because, you know, the whole country is going through the same problem.”

Many Chicago-area hospitals have delayed non-emergency surgeries, a strategy used to free up resources during the earliest days of the pandemic when vaccines were not available. Gov. JB Pritzker and the Illinois Health and Hospital Association last month urged health care providers to postpone many elective surgeries in anticipation of a post-holiday surge in COVID-19 cases.

But some non-emergency surgeries are not optional, health experts say, and delays can have consequences, such as prolonged pain and illness.

“It’s dangerous right now,” said Murphy of Northwestern University’s Feinberg School of Medicine. “Because as soon as you start putting off these, what they call non-urgent surgeries and procedures, you stop screening patients who are otherwise ill.”

Hunter Clauss is a digital editor and writer of WBEZ’s daily newsletter, The Rundown. You can follow him @whuntah.

Anna Savchenko covers higher education for WBEZ. Follow her @WBEZeducation and @annasavchenkoo.