About 2 a.m. on a sweltering summer night, Dr. Orlando Garner awoke to the sound of a thud next to his baby daughter’s crib. He leapt out of bed to find his wife, Gabriela, passed out, her forehead hot with the same fever that had stricken him and his son, Orlando Jr., then 3, just hours before. Two days later, it would hit their infant daughter, Veronica.

Nearly five months later, Dr. Garner, a critical care physician at the Baylor College of Medicine in Houston, is haunted by what befell his family last summer: He had inadvertently shuttled the coronavirus home, and sickened them all.

“I felt so guilty,” he said. “This is my job, what I wanted to do for a living. And it could have killed my children, could have killed my wife — all this, because of me.”

With the case count climbing again in Texas, Dr. Garner has recurring nightmares that one of his children has died from Covid. He’s returned to 80-hour weeks in the intensive care unit, donning layers of pandemic garb including goggles, an N95 respirator, a protective body suit and a helmet-like face shield that forces him to yell to be heard.

As he treats one patient after another, he can’t shake the fear that his first bout with the coronavirus won’t be his last, even though reinfection is rare: “Is this going to be the one who gives me Covid again?”

Frontline health care workers have been the one constant, the medical soldiers forming row after row in the ground war against the raging spread of the coronavirus. But as cases and deaths shatter daily records, foreshadowing one of the deadliest years in American history, the very people whose life mission is caring for others are on the verge of collective collapse.

In interviews, more than two dozen frontline medical workers described the unrelenting stress that has become an endemic part of the health care crisis nationwide. Many related spikes in anxiety and depressive thoughts, as well as a chronic sense of hopelessness and deepening fatigue, spurred in part by the cavalier attitudes of many Americans who seem to have lost patience with the pandemic.

Surveys from around the globe have recorded rising rates of depression, trauma and burnout among a group of professionals already known for high rates of suicide. And while some have sought therapy or medications to cope, others fear that engaging in these support systems could blemish their records and dissuade future employers from hiring them.

“We’re sacrificing so much as health care providers — our health, our family’s health,” said Dr. Cleavon Gilman, an emergency medicine physician in Yuma, Ariz. “You would think that the country would have learned its lesson” after the spring, he said. “But I feel like the 20,000 people that died in New York died for nothing.”

Many have reached the bottom of their reservoir, with little left to give, especially without sufficient tools to defend themselves against a disease that has killed more than 1,000 of them.

“I haven’t even thought about how I am today,” said Dr. Susannah Hills, a pediatric head and neck surgeon at Columbia University. “I can’t think of the last time somebody asked me that question.”

Dreading the darkness of winter

For Dr. Shannon Tapia, a geriatrician in Colorado, April was bad. So was May. At one long-term care facility she staffed, 22 people died in 10 days. “After that number, I stopped counting,” she said.

A bit of a lull coasted in on a wave of summer heat. But in recent weeks, Dr. Tapia has watched the virus resurge, sparking sudden outbreaks and felling nursing home residents — one of the pandemic’s most hard-hit populations — in droves.

“This is much, much worse than the spring,” Dr. Tapia said. “Covid is going crazy in Colorado right now.”

Dr. Tapia bore witness as long-term care facilities struggled to keep adequate protective equipment in stock, and decried their lack of adequate tests. As recently as early November, diagnostic tests at one home Dr. Tapia regularly visits took more than a week to deliver results, hastening the spread of the virus among unwitting residents.

Some nursing home residents in the Denver area are getting bounced out of full hospitals because their symptoms aren’t severe, only to rapidly deteriorate and die in their care facilities. “It just happens so fast,” Dr. Tapia said. “There’s no time to send them back.”

The evening of Nov. 17, Dr. Tapia fielded phone call after phone call from nursing homes brimming with the sick and the scared. Four patients died between 5 p.m. and 8 a.m. “It was the most death pronouncements I’ve ever had to do in one night,” she said.

Before the pandemic, nursing home residents were already considered a medically neglected population. But the coronavirus has only exacerbated a worrisome chasm of care for older patients. Dr. Tapia is beleaguered by the helplessness she feels at every turn. “Systematically, it makes me feel like I’m failing,” she said. “The last eight months almost broke me.”

At the end of the summer, Dr. Tapia briefly considered leaving medicine — but she is a single parent to an 11-year-old son, Liam. “I need my M.D. to support my kid,” she said.

It goes on and on and on

For others, the slog has been relentless.

Dr. Gilman, the emergency medicine physician in Yuma, braced himself at the beginning of the pandemic, relying on his stint as a hospital corpsman in Iraq in 2004.

“In the military, they train you to do sleep deprivation, hikes, marches,” he said. “You train your body, you fight an enemy. I began running every day, getting my lungs strong in case I got the virus. I put a box by the door to put my clothes in, so I wouldn’t spread it to my family.”

The current crisis turned out to be an unfamiliar and formidable foe that would follow him from place to place.

Dr. Gilman’s first coronavirus tour began as a resident at New York-Presbyterian at the height of last spring. He came to dread the phone calls to families unable to be near their ailing relatives, hearing “the same shrill cry, two or three times per shift,” he said. Months of chaos, suffering and pain, he said, left him “just down and depressed and exhausted.”

“I would come home with tears in my eyes, and just pass out,” he said.

The professional fallout of his Covid experience then turned personal.

Dr. Gilman canceled his wedding in May. His June graduation commenced on Zoom. He celebrated the end of his residency in his empty apartment next to a pile of boxes.

“It was the saddest moment ever,” he said.

Within weeks, he, his fiancée, Maribel, their two daughters and his mother-in-law had relocated to Arizona, where caseloads had just begun to swell. Dr. Gilman hunkered down anew.

They have weathered the months since in seclusion, keeping the children out of school and declining invitations to mingle, even as their neighbors begin to flock back together and buzz about their holiday plans.

There are bright spots, he said. The family’s home, which they moved into this summer, is large, and came with a pool. They recently adopted a puppy. Out in the remoteness of small-town Arizona, the desert has delighted them with the occasional roadrunner sighting.

Since the spring, Dr. Gilman has become a social media tour de force. To document the ongoing crisis, he began publishing journal entries on his website. His Twitter wall teems with posts commemorating people who lost their lives to Covid-19, and the health workers who have dedicated the past nine months to stemming the tide.

It’s how he has made sense of the chaos, Dr. Gilman said. What he’s fighting isn’t just the virus itself — but a contagion of disillusionment and misinformation, amid which mask-wearing and distancing continue to flag. “It’s a constant battle, it’s a never-ending war,” he said.

Reaching the breaking point

Nurses and doctors in New York became all too familiar with the rationing of care last spring. No training prepared them for the wrath of the virus, and its aftermath. The month-to-month, day-to-day flailing about as they tried to cope. For some, the weight of the pandemic will have lingering effects.

Shikha Dass, an emergency room nurse at Mount Sinai Queens, recalled nights in mid-March when her team of eight nurses had to wrangle some 15 patients each — double or triple a typical workload. “We kept getting code after code, and patients were just dying,” Ms. Dass said. The patients quickly outnumbered the available breathing support machines, she said, forcing doctors and nurses to apportion care in a rapid-fire fashion.

“We didn’t have enough ventilators,” Ms. Dass said. “I remember doing C.P.R. and cracking ribs. These were people from our community — it was so painful.”

Ms. Dass wrestled with sleeplessness and irritability, sniping at her husband and children. Visions of the dead, strewn across emergency room cots by the dozens, swam through her head at odd hours of the night. Medical TV dramas like Grey’s Anatomy, full of the triggering sounds of codes and beeping machines, became unbearable to watch. She couldn’t erase the memory of the neat row of three refrigerated trailers in her hospital parking lot, each packed with bodies that the morgue was too full to take.

One morning, after a night shift, Ms. Dass climbed into her red Mini Cooper to start her 20-minute drive home. Her car chugged onto its familiar route; a song from the 2017 film “The Greatest Showman” trickled out. For the first time since the pandemic began, Ms. Dass broke down and began to cry. She called her husband, who was on his way to work; he didn’t pick up. Finally, she reached her best friend.

“I told her, ‘These people are not going to make it, these people are not going to survive this,’” she said. “We’re there to save a person, save a life, stabilize a person so they can get further management. And here I am, not able to do that.”

Shortly after, she phoned a longtime friend, Andi Lyn Kornfeld, a psychotherapist who said Ms. Dass was in the throes of “absolute and utter acute PTSD.”

“I have known Shikha for 13 years,” Ms. Kornfeld said. “She is one of the strongest women I have ever met. And I had never heard her like this.”

The sounds of silence

Long gone are the raucous nightly cheers, loud applause and clanging that bounced off buildings and hospital windows in the United States and abroad — the sounds of public appreciation at 7 each night for those on the pandemic’s front line.

“Nobody’s clapping anymore,” said Dr. Jessica Gold, a psychiatrist at Washington University in St. Louis. “They’re over it.”

Health workers, once a central part of the coronavirus conversation, have in many ways faded into the background. Some, like Dr. Gilman, in Arizona, have had their salaries slashed as hospitals weigh how to cover costs.

Many have guiltily recoiled from the “hero” label emblazoned in commercials or ad campaigns, burdened by the death march of the people they could not save and the indiscriminate path of the coronavirus.

The word “hero” evokes bravery and superhuman strength but leaves little room for empathy, said Dr. Nicole Washington, a psychiatrist in Oklahoma. When portrayed as stalwart saviors, health workers “don’t have the room or right to be vulnerable.”

But the trope of invincibility has long been ingrained into the culture of medicine.

Dr. Tapia, the Colorado geriatrician, began taking an antidepressant in September after months of feeling “everything from angry to anxious to furious to just numb and hopeless.” The medication has improved her outlook. But she also worries that these decisions could jeopardize future employment.

Many state medical boards still ask intrusive questions about physicians’ history of mental health diagnoses or treatments in applications to renew a license — a disincentive to many doctors who might otherwise seek professional help.

Being on the front lines doesn’t make health workers stronger or safer than anyone else. “I’m not trying to be a hero. I don’t want to be a hero,” Dr. Gilman said. “I want to be alive.”

As social bubbles balloon nationwide in advance of the chilly holiday months, health care workers fret on the edges of their communities, worried they are the carriers of contagion.

Dr. Marshall Fleurant, an internal medicine physician at Emory University, has the sense that his young children, 3 and 4 years old, have grown oddly accustomed to the ritual of his disrobing out of work clothes, from his scrubs to his sneakers, before entering his home.

“I do not touch or speak to my children before I have taken a shower,” Dr. Fleurant said. “This is just how it is. You do not touch Daddy when he walks in the door.”

A week of vacation with his family startled him, when he could scoop the little ones up in his arms without fear. “I think they must have thought that was weird,” he said.

Bracing for the next wave

Trapped in a holding pattern as the coronavirus continues to burn across the nation, doctors and nurses have been taking stock of the damage done so far, and trying to sketch out the horizon beyond. On the nation’s current trajectory, they say, the forecast is bleak.

Jina Saltzman, a physician assistant in Chicago, said she was growing increasingly disillusioned with the nation’s lax approach to penning in the virus.

While Illinois rapidly reimposed restrictions on restaurants and businesses when cases began to rise, Indiana, where Ms. Saltzman lives, was slower to respond. In mid-November, she was astounded to see crowds of unmasked people in a restaurant as she picked up a pizza. “It’s so disheartening. We’re coming here to work every day to keep the public safe,” she said. “But the public isn’t trying to keep the public safe.”

Since the spring, Dr. Gilman has watched three co-workers and a cousin die from the virus. Ms. Dass lost a close family friend, who spent three weeks at Mount Sinai Queen’s under her care. When Dr. Fleurant’s aunt died of Covid, “We never got to bury her, never got to pay respects. It was a crushing loss.”

In state after state, people continue to flood hospital wards, where hallways often provide makeshift beds for the overflow. More than 12 million cases have been recorded since the pandemic took hold in the United States, with the pace of infection accelerating in the last couple months.

Jill Naiberk, a nurse at the University of Nebraska Medical Center, has spent more of 2020 in full protective gear than out of it. About twice a day, when Ms. Naiberk needs a sip of water, she must completely de-gown, then suit up again.

Otherwise, “you’re hot and sweaty and stinky,” she said. “It’s not uncommon to come out of rooms with sweat running down your face, and you need to change your mask because it’s wet.”

It’s her ninth straight month of Covid duty. “My unit is 16 beds. Rarely do we have an open one,” she said. “And when we do have an open bed, it’s usually because somebody has passed away.”

Many of her I.C.U. patients are young, in their 40s or 50s. “They’re looking at us and saying things like, ‘Don’t let me die’ and ‘I guess I should have worn that mask,’” she said.

Sometimes she cries on her way home, where she lives alone with her two dogs. Her 79-year-old mother resides just a couple houses away.

They have not hugged since March.

“I keep telling everybody the minute I can safely hug you again, get ready,” she said. “Because I’m never letting go.”