Alexandria Ocasio-Cortez says the toll of the virus in her district has made the case for more health care and less income inequity. But it has also exposed the vulnerabilities and isolation of her voice in Congress.

The dash to overnight millennial celebrity can take abrupt detours.

Representative Alexandria Ocasio-Cortez, the democratic socialist from the Bronx, was propelled from an anonymous existence as a bartender after her upset victory in 2018 straight onto magazine covers, late-night TV and the top of every partisan love-hate list in America. It made her perhaps the most exposed and fixated-on House freshman in history.

Today, the youngest woman ever elected to Congress — known simply as A.O.C. — owns another distinction, this one far grimmer: She represents the nation’s most devastated hot zone of the coronavirus outbreak.

New York’s 14th Congressional District, which includes the working-class immigrant clusters of the Bronx and Queens, has had 19,200 coronavirus cases as of April 30, more than all of Manhattan, despite having almost a million fewer people. Residents of the neighborhoods of Corona and North Corona in her district — the names are an eerie coincidence — have had more coronavirus cases than any ZIP code in the country.

Ms. Ocasio-Cortez, 30, knows many who have died, as well as others who were sickened with the virus, or left hungry or jobless. She sends notes and makes calls to as many surviving family members as she can, serving as a kind of legislative first responder. But it can be hard to keep up.

“I’ll be on calls with service workers, front-line workers, and they’re the ones who have to pull bodies out of apartments,” she said, sitting in her empty and freezing campaign headquarters in the Bronx on a recent afternoon, surrounded by bags of donated food she was preparing to deliver to families in her district. The usually crowded streets were quiet, except for a steady assault of rain and sirens.

“There’s just so much first-, second- and third-degree trauma here,” she said.

She wore no mask, either to protect her face from germs during this interview (conducted at a 12-foot distance) or to cover up her emotions generally. The wreckage in her community has made a darkly eloquent case, she said, for her agenda of universal health care and less income inequity. “This crisis is not really creating new problems,” she said. “It’s pouring gasoline on our existing ones.”

But more personally, it has exposed the little-seen vulnerabilities and isolation of the most prominent new voice in Congress.

A case in point: Ms. Ocasio-Cortez had just returned from Washington after a vote last month on the latest relief bill in Congress. She was the only Democrat to vote against the $484 billion package that passed overwhelmingly. She had many problems with the measure: Generally, she found it far too generous to corporations and not to local governments, small businesses and people struggling to buy food or pay rent.

Several colleagues had told her they also disliked the legislation, but it was not until right before the vote that she realized she would be by herself. Passage was never in doubt, but to be the lone member of a caucus to vote a certain way carries its own stigma.

“Our brains are just designed to experience a lot of excruciating pain at the idea of being alone,” Ms. Ocasio-Cortez said. “When you cast those lonely votes, you feel like your colleagues respect you less, and that you are choosing to marginalize yourself.” It can be difficult to appreciate the “powerful psychology of the House floor,” she said, along with the overall social pressures of Congress.

“I walked home in the rain,” Ms. Ocasio-Cortez said, describing her mood after the bill passed. “I was very in my feelings, big time, and I felt very discouraged.” She said she would have appreciated, at least, a heads-up from the colleagues who had said they were probably no votes but then flipped at the last minute.

“I was just, like, heartbroken,” she said.

Ms. Ocasio-Cortez’s colleagues are, for the most part, farther removed from the virus’s daily toll, which has only heightened the alienation she felt when she arrived on Capitol Hill last year. “I have, like, existential crises over it,” she said.

At the root of this has been the hardship the pathogen has imposed on where she lives, something that can be difficult to appreciate from the sanctuary of the Capitol. New York’s 14th Congressional District comprises a patchwork of diverse, vibrant and vulnerable urban communities covering the eastern part of the Bronx and north-central Queens. Roughly half of the predominantly working-class population is of Hispanic descent. They make up many of the city’s grocery workers, transit operators, custodians and child care providers, 75 percent of whom are minorities.

Nearly everyone in the district has had some personal connection to someone lost to the virus. They include Lorena Borjas, a 59-year-old transgender immigrant activist in Queens and Mohammad Gias Uddin, a 64-year-old Bangladeshi community leader who ran A&A Double Discount in the Bronx. Ms. Ocasio-Cortez knew both of them, as well as others she called “strong anchors” in the community.

“Just this morning, we were just talking to our landlord here who had just lost his brother,” she said. “Both of his children are hospital workers.” She speaks all the time to people who cannot afford food, rent and burials. The catastrophe is woven tightly into her day-to-day fabric.

It is not the same for many members of Congress, a world far from the shuttered taquerias, overrun emergency rooms and refrigerator trucks doubling as makeshift morgues that sit within a few miles of Ms. Ocasio-Cortez’s home in the Bronx. The disconnected reality contributes to her sense of feeling misunderstood by her colleagues, something she felt well before the virus ravaged her district.

“I felt like my colleagues were making opinions about me based on Fox News,” she said. “It almost felt like instead of them actually talking to the person who was next to them, and physically present in front of them, they were consuming me through television. And I think that added a lot to the particular loneliness that I experienced.”

Rookie stardom carries its own isolation in Congress, a habitat filled with some of the planet’s most jealous and thirsty creatures. Ms. Ocasio-Cortez has owned her outsize profile, for better or worse, since beating a 10-term incumbent, Representative Joseph Crowley, in the 2018 Democratic primary. “You come in and you have a stunning victory, and for whatever reason the media has turned you into a sensation,” said Representative Peter Welch, Democrat of Vermont. “It’s quite a situation to come into.”

Ms. Ocasio-Cortez once made an off-handed remark about how she felt like kissing the ground whenever she returned to New York. A senior colleague chastised her. “You know, I heard what you said,” he told her. “Being here is a privilege.” Yes, of course it was, she reassured him. Serving in Congress was “the greatest privilege of my life,” she added. Of the exchange with that colleague, Ms. Ocasio-Cortez summarized it like this: “It’s one of those small interactions that will kind of lead to sadness later.”

She believed misconceptions had taken hold about her: that she was angry and strident. That she was naïve. “That I just don’t know how this town works,” she said. “That I’m stupid. Or I’m lucky. That was a big thing the Democrats were saying. That I was a fluke. Which is basically just 10 different ways of saying she’s not supposed to be here.”

Ms. Ocasio-Cortez’s life trajectory has always involved toggling between starkly distinct worlds. When she was 5, her parents moved the family from their apartment in the Parkchester section of the Bronx to Yorktown, in Westchester County, so that she and her brother could attend better schools. She would sometimes join her mother, who worked as a house cleaner, to help scrub the homes of the neighbors, including that of a school tutor, which she cleaned in exchange for SAT lessons.

She attended Boston University, another enclave of relative wealth and privilege that brought its own culture shock. “The first week everyone was asking each other, ‘What school did you go to?’ And I was like, ‘Uh, public high school,’” she said. “There were all of these unwritten social cues. Everyone knew how to dress.”

In mid-March, when some of the first coronavirus cases started showing up in the United States but before its rapid spread, Ms. Ocasio-Cortez was mostly sheltered at home like everyone else — in her case, the Parkchester apartment she shares with her boyfriend, Riley Roberts, and a French bulldog named Deco. Getting to spend time in her district has been grounding, she said, despite all the despair. It has allowed Ms. Ocasio-Cortez to perform tactile work in her community, reclaiming her previous role as a grass-roots activist.

Still, national intrigue will inevitably find her. She was a high-profile supporter of Senator Bernie Sanders’s presidential campaign and remains a coveted potential endorsement for former Vice President Joseph R. Biden Jr., the presumptive Democratic presidential nominee. Her policy positions, she said, have only been affirmed by the damage the coronavirus has inflicted, disproportionately, upon lower-income populations.

“When everything started to hit the fan,” Ms. Ocasio-Cortez said, the more moderate Democrats “had no answers. There was no policy.” Her liberal wing did, she said. “It’s just doing progressive things faster,” she said, mentioning higher wages, hazard pay and lowering the age of Medicare eligibility to zero. “There is no argument from the more conservative part of the party to countervail that.”

While Ms. Ocasio-Cortez said she would support the person Democrats nominate to face President Trump, she has to this point resisted. She is wary of questions that suggest Mr. Biden must do certain things to earn her support, which she says could smack of self-importance.

But Ms. Ocasio-Cortez barely hides her lack of enthusiasm for Mr. Biden, although she says she believes that the comfort he engenders could buy him ideological latitude. “I think the fact that he is an older white man kind of has a Santa Claus soothing effect on a lot of traditional voters,” she said. “I’m convinced that Biden could essentially adopt Bernie’s agenda, and it would not be a factor — as long as he continued to say things like malarkey. And just not be Trump.”

Speculation about Ms. Ocasio-Cortez’s career moves has been another distraction. She has been mentioned as a potential primary challenger in 2022 to Senator Chuck Schumer of New York, the minority leader — an idea that is a particular hobbyhorse of Mr. Trump’s. The New York Times columnist Thomas L. Friedman has also floated her as an American ambassador to the United Nations in a Biden administration.

“Probably not,” she said when asked about serving in a Biden government, although the Friedman column did get her attention, given the U.N.’s headquarters in New York.

“That was the one perk of this,” she said. “I would get to stay home.”