SPRINGFIELD, Mo. — The worst of the pandemic seemed behind Mercy Hospital, those weeks last winter when the coronavirus wards were full of people struggling to breathe.

But after months of reprieve, the virus has come roaring back, sending unvaccinated young adults and middle-aged patients from across southwest Missouri there in droves as the highly transmissible delta variant tears through the region. The hospital has been treating more than 130 covid-19 patients each day since Sunday — more than the winter surge — and had to open a sixth ward. It came close to running out of ventilators earlier this month.

“We’re just very disheartened. This was all pretty avoidable,” said Wanda Brown, a nurse unit manager. “Last year, we were looking forward to the vaccine coming out because we really thought that that was going to be helpful for our community. We feel like we’ve taken giant leaps backward.”

Springfield, a city of 170,000 nestled in the Ozarks, has become a cautionary tale for how the more transmissible delta variant, now estimated to account for half of all new cases nationwide, can ravage poorly vaccinated communities and return them to the darkest days of the pandemic.

Missouri has reported one of the nation’s highest per capita increases in new coronavirus cases in recent weeks. Freeman Health System in Joplin, about 70 miles west of Springfield, announced the full reopening of its covid-19 ward in late June after downsizing in the spring because of a lack of patients. The delta variant has been linked to a broader regional outbreak spilling into Arkansas and Oklahoma, as well as emerging hot spots in Louisiana, Florida, Nevada, Utah and Wyoming. Cases and hospitalizations are strongly correlated with low vaccination rates, according to a Washington Post analysis.

Nationally, the coronavirus case rate has more than doubled since late June. The national vaccination rate has settled at close to 500,000 doses per day, one-sixth of the more than 3 million per day in mid-April.

Experts fear that the surge in Springfield, known as the birthplace of Bass Pro Shops and Andy’s Frozen Custard, is a harbinger of tensions to come as people play down the pandemic and refuse to get vaccinated even in the face of overwhelmed hospitals and preventable death. Instead of unifying the community, the surge has hardened divisions, unleashing anger from health-care workers fed up with vaccine misinformation and exposing deep antipathy toward the public health establishment.

New infections are rapidly rising to levels not seen since early January, prompting the school system to reinstate a mask mandate for summer school. Almost every virus sample sequenced in June turned out to be the delta variant, which is significantly more transmissible than the strain that first arrived in the United States. Local health officials are trying to create an alternate care site for stable covid-19 patients as Wednesday’s 231 hospitalizations are on the verge of an all-time peak and are projected to surge beyond available capacity.

Coronavirus deaths in Greene County, where Springfield is located, had plunged this spring, but 23 people have succumbed since June 21. All but one were unvaccinated. The fire chief described the outbreak as a “mass-casualty event, happening in slow-motion.”

The Springfield-Greene County Health Department has prioritized vaccination in a county where only 35 percent of residents are fully vaccinated, according to data from the Centers for Disease Control and Prevention. Rates are even lower for people in their 20s and 30s. But new daily vaccinations have largely stayed flat through June despite the outbreak’s toll, and health officials are battling false theories that the vaccines are somehow responsible for a surge in hospitalizations almost exclusively affecting the unvaccinated.

“It’s a sad reality that we are facing,” said Katie Towns, the acting health director. “I don’t think we are coming out of it anytime soon. We are going to see more people get really sick. We are going to see a lot of people die.”

‘You get it, and you give it to your mom’

Katlyn Mozingo, a 19-year-old rising sophomore at Springfield-based Missouri State University, carries the guilt of almost certainly infecting her mother.

Mozingo, who has severe allergies to nuts and certain medications, held off on a shot until after a July 20 appointment with her allergist to discuss the potential risks of vaccines. Her mother, Leanne Mozingo, 48, also waited, worried about side effects as a result of her complicated medical history, including ailments her doctors couldn’t diagnose.

But the coronavirus came home after Katlyn contracted a mild case after hanging out with a friend who also tested positive. Leanne wore a mask as she brought her daughter vegan chicken strips and would disinfect the bathroom regularly with Lysol. After her daughter recovered, Leanne’s throat began to ache. She started regularly using oxygen she would normally only use at night for her sleep apnea.

After waking up in the middle of the night screaming for help because she couldn’t breathe, Leanne was taken to a hospital by ambulance. Within days, she was on a ventilator. Katlyn hoped her mother would persevere, as she had done through severe bouts of depression and anxiety, stomach surgery, chronic pulmonary obstructive disorder, endometriosis and other chronic pain.

She embraced her sedated mother one last time on June 27 before doctors removed the ventilator. Her brother, DJ, who has autism and relied on his mother as a primary caregiver, watched their mother die on FaceTime from the hospital parking lot, unable to step inside because he was also infected.

“I keep on telling everyone she’s going to come home in a week, and we are going to be a big family again,” Katlyn Mozingo said. “We as young people don’t understand, because we feel like we are healthy and next thing you know, you get it, and you give it to your mom and she passes.”

‘It’s two different worlds that people are in’

Doctors and nurses are fighting to overcome the perception that young adults do not need to worry about contracting the virus when they see evidence to the contrary every day.

“I’m seeing some people in their 30s and 40s that don’t have underlying health conditions, and they are very ill with this,” said Howard Jarvis, the emergency room medical director at CoxHealth South. “And sometimes they’re not so ill that they have to be admitted. They may be back in three or five days and do need to be admitted.”

CoxHealth, which is locally owned and the other major hospital in Springfield, publicized videos of bedside interviews of covid-19 patients urging people to get vaccinated and posted about a man in his 40s who told nurses he wished he had been vaccinated before he was intubated and later died.

But those posts also unleash comments from people doubting the severity of the surge. The skepticism isn’t all online.

One of Jarvis’s patients initially refused to get tested for the coronavirus, relenting only after other tests ruled out other illnesses. Jarvis still hears the occasional insistence on the false claim that vaccines contain tracking microchips.

Hospital officials also say some patients have refused monoclonal antibodies proven effective when administered during early covid-19 treatment and demanded hydroxychloroquine promoted by Donald Trump during his presidency, even though studies have found that it is not effective.

U.S. Surgeon General Vivek Murthy issued an advisory Thursday calling misinformation a threat to vaccination efforts and attempts to control the pandemic. “We live in a world where misinformation poses an imminent and insidious threat to our nation’s health,” he said at a news briefing.

Fed up, CoxHealth chief executive Steve Edwards, a frequent social media presence, tweeted July 1: “If you are making wildly disparaging comments about the vaccine, and have no public health expertise, you may be responsible for someone’s death. Shut up.”

That tweet won praise from people seeking catharsis when anti-vaccine voices have been loud and belligerent, but it also unleashed a backlash.

Nick Reed, a local conservative radio talk show host, devoted a show the next day to Edwards’s tweet. He said the message would erode community trust further and make patients with legitimate concerns about side effects more wary of getting honest answers from doctors at CoxHealth.

In an interview, Reed expressed sympathy for health-care workers frustrated from seeing the daily toll of the virus.

“It makes it difficult to understand there are people going about living their life and recognize what’s going on and recognize it can be very deadly and many have lost loved ones, but they have the luxury of standing back and evaluating the situation as a whole and wondering about the long-term effects of vaccines,” Reed said. “It’s two different worlds that people are in, and sometimes we don’t give grace and understanding to the other person’s world, and that can lead to this separation.”

Edwards stood by his tweet, which he said was clearly targeting people spreading false information and not those concerned about side effects.

“This is my hometown. I don’t treat it as a job. … When I’ve been in our covid ICU, I’ve seen people I know and it breaks my heart,” Edwards said in an interview. “I really don’t care about any kind of backlash I get by speaking the words that I do that I think will save lives.”

Johns Hopkins University epidemiologist Gypsyamber D'Souza explains how the U.S. can reach coronavirus herd immunity and what happens if that goal is missed. (Brian Monroe, John Farrell/The Washington Post)

‘We are feeling a lot of frustration and anger’

The CDC has deployed two staff members to assist in Springfield’s coronavirus response, including one focused on improving the communications strategy for vaccine holdouts.

A major barrier is conservative reluctance in a county that Trump won by 20 percentage points and by even broader margins in the neighboring rural counties. A recent Washington Post-ABC poll found that nearly half of Republicans probably will not get their shots and that the Midwest is the most vaccine-averse region, with 27 percent saying they definitely will not get vaccinated.

Some Republican politicians have been vocal in urging their constituents to get vaccinated. They’ve been more muted in Missouri, where Gov. Mike Parson (R) has described vaccination as a “personal responsibility” and said health-care leaders need to stop trying to “scare” people into taking vaccines. He also instructed the state health department not to cooperate with the Biden administration on door-to-door vaccine outreach, even though local health authorities have been canvassing homes. Parson’s office did not respond to a request for comment.

Towns, the acting health director, lamented that door-to-door outreach has joined the ranks of masks and vaccines as the latest routine public health practice lambasted by politicians. “It’s just unfortunate they’ve been politicized, because we are trying to combat a silent killer while also making people trust us,” she said.

The partisan divides are also playing out in contentious family discussions about the virus.

Hannah Brashers, a 27-year-old who works in Democratic politics, said she and other liberal friends worry about their conservative parents living in the nearby rural counties with much lower vaccination rates. Brashers has been trying to get her diabetic father to get vaccinated after the mother of one of her friends came close to death.

He’s not ardently opposed to vaccines, Brashers said, but instead worried about the lack of research on long-term side effects and reports of people who still become infected after vaccination. Brashers countered that those cases are far less likely to result in hospitalization or death.

Her persistence paid off: He called her on FaceTime on Wednesday and showed off the Band-Aid on his arm from his Johnson & Johnson shot. Brashers worries that other Republicans won’t be swayed.

“We are feeling a lot of frustration and anger because our lives are in danger and the lives of the people we love are in danger because there’s so much animosity toward the vaccine by the evangelical and conservative groups in the area,” she said.

Deep skepticism about the latest outbreak was on display outside the Bass Pro Shops complex that draws customers from around the region to buy fishing supplies and guns in a sprawling store that has zoo-like enclosures with alligators and turtles.

Several shoppers, who declined to give their names, described the reports about the delta variant outbreak as “overblown,” “exaggerated” and a “crock of s---.” One woman said that her daughter was hospitalized in an intensive care unit with covid-19 but that she thinks the numbers are exaggerated.

Others took more measured views, such as Billy and Alissa Iorg, a couple from nearby Sparta, Mo. Alissa, who is 24 and pregnant with their second child, declined to get vaccinated because she wasn’t sure how the shots would affect the pregnancy. Billy, 26, didn’t see the rush for himself.

“It’s no worse than the flu,” he said of the virus, which experts say appears to be far more contagious and deadly than the flu.

Fighting a lack of urgency

For some young people who haven’t made up their minds about the vaccines, it’s already too late.

Olivia Bricker, 21, drove to the health department offices for a throat swab after feeling her head throb. Several co-workers at her retail job tested positive for the virus, as did her 25-year-old live-in boyfriend, who “felt like a sack of potatoes.”

They are not anti-vaccine. He previously had the virus. Bricker hadn’t gotten around to getting vaccinated, unsure of which of the three authorized vaccines to choose, and didn’t feel much urgency because older relatives she feared infecting had been immunized.

“I feel like it’s one of those things I probably should have just done instead of waiting,” Bricker said.

Clayton Reed, 30, was visited at his home by Springfield’s vaccine outreach team. One of Reed’s 25-year-old friends has been bedridden for two weeks after he and his mother contracted the virus. But Reed, 30, isn’t too worried for himself because he works an overnight shift at Walmart and has little interaction with other employees or customers.

The day after the outreach team canvassed the neighborhood and left fliers advertising free vaccines at a nearby church, just 19 people showed up.

There were still some glimmers of hope that more holdouts would come off the fence. Iliza Branson, 30, arrived with her sister after their aunt’s friend recently died of covid-19 and their employer called workers back to the office.

“It’s better to have it than not have it,” said Branson, who said she is a descendant of the family that founded the nearby tourist destination city bearing the same name. “Plus, I have three kids and I don’t want to die because of this.”

Facing the prospect of many young people still feeling relatively safe from the virus, vaccine proponents are trying to urge them to protect their elders and friends who have preexisting conditions and may not be as lucky.

Katlyn Mozingo thinks about that social responsibility as she prepares to return to campus, where many of her classmates are in no hurry to get vaccinated.

On a Friday evening, Leanne Mozingo’s family gathered in the home where wilted flowers rested on the mantel and grief started to give way to planning life without her.

DJ, 22, who has struggled to process the loss of his mother and biggest support system, has been turning more to his grandmother, sister and his mother’s longtime boyfriend, Justin Brown, as he navigates adulthood with autism. The family needs to find a new home, unable to pay the $1,400 rent without Leanne’s disability payments. They plan to hold a garage sale to downsize and raise money for a move.

Brown unenthusiastically got his shots after his employer offered two hours of pay for each dose.

“I just kind of thought covid in general was a joke and you hear stories about how it had a 97 percent survival rate,” said Brown, 27. “I was around covid in the thick of it for the better part of 30 days, and I’m vaccinated and never got a single symptom.”

He added: “Maybe you are getting chipped or all these other conspiracies they’re talking about. But at the end of the day, it’s clearly doing something.”

Marisa Iati and Dan Keating in Washington contributed to this report.