California healthcare workers didn't know they were fighting a new variant this winter. Their trauma should be a warning.

• Southern California's winter surge of COVID-19 infections overwhelmed hospitals.
• A new variant of the virus became dominant there, which may have partially spurred the surge.
• Four healthcare workers in San Diego and Los Angeles share their stories from the winter.

Shawna Blackmun-Myers grasped her patient's hand, called the woman's family, and held up the phone. As everyone said their goodbyes on the other end, the patient couldn't respond: A tube down her throat was feeding oxygen from a ventilator into her lungs.

Blackmun-Myers, an ICU nurse at the Jacobs Medical Center in San Diego, told Insider that the woman was in her 50s and had been bubbly when she came in weeks earlier. Normally in the ICU, Blackmun-Myers said, "people are so sick that that energy and that light is dimmed, but even her being in that situation, she was still just such a bright light."

"We were dancing and listening to music, and we were watching some soap opera drama stuff on TV and, you know, talking tea about everybody," she added.

But the woman's condition worsened quickly. Hospital staff readied a ventilator.

"She's crying and telling me, you know, 'I just don't want to be alone. And I just know that once this tube goes in, I don't think it's coming out. I think this is going to be it,'" Blackmun-Myers said.

"I did my best to let her know, you know, obviously she's not alone. I was there with her. I had her back," she added.

Then the virus brought heart and kidney problems. The woman went on dialysis. Eventually, there was nothing more the hospital could do to restore her quality of life, and her family knew she wouldn't want to live this way.

In January, Blackmun-Myers oversaw the woman's death as hospital staff disconnected the ventilator. The sound of crying family members echoed through the phone.

It was the middle of winter in Southern California. Coronavirus cases were at an all-time high, and ICUs were above 90% capacity. Blackmun-Myers's unit was losing multiple patients every day.

"I ugly-cry, and then I get angry, and I accept the fact that I did everything I could," she said. "And just move on so I can take care of the next person and their family."

Blackmun-Myers didn't know it at the time, but a new coronavirus variant had been overtaking the region.

The CAL.20C variant was first identified in Los Angeles in July, then disappeared from the record until October. But by January, it accounted for 44% of Southern California coronavirus samples in one study, and more than half of California samples in another.

Several other factors contributed to Southern California's winter surge - holiday travel, crowded housing, pandemic fatigue - but many researchers think the variant played a role.

Two studies that aren't yet peer-reviewed suggest that the variant is more infectious than the original virus strain. The research also found it to be associated with a higher incidence of severe illness and partially resistant to antibodies developed in response to the original virus or vaccines.

Although California cases have dropped from a peak of about 40,700 per day in late December to about 4,000 now, experts warn that CAL.20C or other variants could still change the course of the pandemic.

"Now is not the time to relax the critical safeguards that we know can stop the spread of COVID-19 in our communities," Dr. Rochelle Walensky, the CDC director, said at a White House briefing last week.

"Please hear me clearly," she added. "At this level of cases, with variants spreading, we stand to completely lose the hard-earned ground we have gained."

Blackmun-Myers and three other Southern California healthcare workers say what they saw this winter should serve as a strong warning.

Struggling to be heard

Nurse Kristine Chieh doesn't normally work in the ICU, but in January the COVID floors of the Sharp hospital network in San Diego needed all the help they could get.

Two days before her first ICU shift, Chieh's friend, a man in his late 40s, died from COVID-19 after more than two weeks in the hospital.

"I walked through the ICU, looking at the windows, and I swear I see my friend over and over and over again in those beds," she said.

Chieh recalled stopping to help a man video chat with his family. A mask covered his face, pumping oxygen from a BiPap machine. Chieh lifted the mask for short intervals so he could speak to his family. After a few seconds, he would run out of breath, and Chieh would put the mask back down. Family members would speak up to fill the silence.

"There's all kinds of people on that iPad, like he must have a large family," Chieh said. "They thought it was so awesome to be able to hear his voice, and I think he was really excited to use his voice."

She spent about half an hour like that, lifting and lowering the mask.

"The other ICU nurse was in the process of intubating somebody at the same time that this is happening, so there's no way she would have been able to do that for him," Chieh said. "I clocked out for the day and I don't know what ever happened to him, long term. Hopefully he made it out okay."

'It almost overtook my vocabulary and my mind'

Chieh works as a float nurse across three locations in the Sharp hospital network, going wherever she's needed. Typically, she works in progressive care units - the level before intensive care. But during the winter, even the COVID-19 patients there were severely ill. Chieh would dash from room to room, changing in and out of protective gear to help patients who suddenly found themselves struggling to breathe.

"Throughout my shift, I'll get patients who are off and on just being like, 'I can't breathe, I can't breathe.' And then I go in and I do breathing exercises with them. I adjust their oxygen. I have the respiratory therapist come in, do breathing treatments, whatever is needed," Chieh said.

They would calm down and be fine for about an hour, she said, before it happened again.

Those rooms were often loud. Given the influx of coronavirus cases, the Sharp hospitals had to jerry-rig negative-pressure systems to prevent virus particles from wafting out of patients' rooms. The makeshift tubing roared overhead, so Chieh had to yell over it - and through several layers of PPE - for patients to hear her.

Robert Bang, a floor nurse in Los Angeles, spent his winter days the same way. Alarms were constantly sounding through the computer system, he said, to alert him that a patient's oxygen levels had dropped too low. He would rush to the patient's room, sometimes to find that they didn't even realize they were losing oxygen.

"If you've been short of breath for so long, you just start developing fatigue from breathing so hard. So it might be like your new normal," Bang told Insider.

Even when he went home, Bang said, he would still hear the alarms in his head. Work followed Chieh home, too.

"My husband gave me this feedback: I talked about COVID too much at home. Talked about masks too much, talked about every news article," she said. "It almost overtook my vocabulary and my mind."

That hasn't fully subsided - Chieh said those winter days still haunt her.

"I feel like I can remember every single COVID patient," she said. "I imagine what it must be like to have this astronaut person come into their room to work with them. They must be terrified."

'I've never seen something infect people so easily'

Many of Dr. Kenny Pettersen's patients in Los Angeles live in crowded homes with a combination of parents, kids, grandparents, or cousins under one roof. That made it difficult to make quarantine plans for the COVID-19 patients who weren't sick enough to stay at the hospital.

In spring and summer, he told Insider, "when someone in the household would have COVID, usually like half or less of the rest of the household would get COVID."

But this winter, Pettersen, said "it was almost universally 100%."

Pettersen is a primary-care physician at Olive View-UCLA Medical Center. The change in LA's outbreak was so noticeable to him during the winter that he assumed the virus itself must have changed.

"I've never seen something infect people so easily," he said. "I felt like I was almost wasting my time talking to patients about the prevention of household transmission."

More research on CAL.20C is still needed to confirm his suspicions, though, since the initial studies of the variant haven't been peer reviewed, and the spike-protein mutation that characterizes it has not been thoroughly investigated.

Relief and grief after the surge

Pettersen's grandmother died of coronavirus in August. Many of his patients died, too, and some left behind young children. One family is losing their home after the coronavirus-related deaths of two family members.

"Practically every one of my patients, either they've been infected, or many of their family members have been infected, they know somebody very well who has died or gotten severely sick," Pettersen said. "I think the cumulative toll that takes on my patients is just really profound."

Still, he said, the mood among his coworkers is more upbeat now. There are even days at the hospital when nobody dies of COVID-19.

"I think that we can start to breathe with a little bit more confidence," Pettersen said. He and his wife have both been vaccinated.

Bang and Chieh say they feel safer these days, too. The volume of COVID-19 patients is much lower. They've been vaccinated, and more people are getting shots each day. But the winter memories persist. Some healthcare workers are now nervous about other variants. And there's a strong possibility they or their colleagues will develop PTSD.

But Pettersen, at least, said he was finally able to go to an outdoor restaurant for sushi with his wife recently.

"We can, you know, be optimistic for the first time in about a year," he said.