When the first COVID-19 cases appeared in Detroit, there was a broad but nonspecific panic, and emergency departments across southeastern Michigan were flooded with coughing people who were more worried than ill. In the past week, that flood has abated; the patients who are coming in now are sicker, and often in immediate need of oxygen. Most visitors to hospitals have been banned and many departments emptied of patients, and so physicians report a spooky juxtaposition between the crisis atmosphere of the expanded I.C.U.s and the bureaucratic calm of the rest of the building. “I used to occasionally do employee rounds on the midnight shift, and you would see these usually busy, wide hallways, your main thoroughfares, just empty, and it would always be such a strange feeling,” Bob Riney, the chief operating officer of Henry Ford Health System, told me. “And now you see that in the middle of the day.”

The coronavirus pandemic has had a way of turning even the most prestigious hospitals into community-health operations. Henry Ford Hospital, in downtown Detroit, one of the largest teaching hospitals in the country, is building a unit for forty-eight skilled-nursing-facility residents who no longer require hospitalization for COVID-19 but whose facilities refuse to take them back. Rana Awdish, who runs the hospital’s pulmonary-hypertension program and practices critical-care medicine, normally spends her days seeing patients who travel to her clinic from across the Midwest. But, since the first coronavirus patients arrived, about three weeks ago, the helicopters and ambulances that transfer patients have stopped almost entirely. The patients filling the COVID-19 units are coming from Detroit.

We are just beginning to see demographic data on those who’ve died of COVID-19, but African-American communities around the country may be especially vulnerable. Black Americans have increased rates of high blood pressure and diabetes, conditions which seem overrepresented in COVID-19 patients who grow critically sick, and in pockets of concentrated poverty those rates can be higher still. In Detroit, where seventy-nine per cent of the population is black and thirty-six per cent is below the poverty line, the diabetes rate is roughly twice the national average. Southeastern Michigan has become a national epicenter of the outbreak, and though African-Americans are just fourteen per cent of the state’s population they represent forty-one per cent of its COVID-19 victims. (On Monday evening, Louisiana released an even starker set of statistics: African-Americans make up roughly thirty-two per cent of the state’s population, but have accounted for seventy per cent of its coronavirus deaths.) Awdish and her colleagues are on the front lines in two senses: in Detroit, the pandemic is escalating in intensity, and poverty and poor health may be changing its shape.

Awdish has made a point of visiting each COVID-19 unit daily, to talk with doctors about what they have seen. As patient numbers in the hospitals have increased, she and her colleagues have begun to notice certain patterns, some of which have emerged nationwide: for instance, COVID-19 patients often seem to hold steady until about eight days after their first symptoms, at which point they suffered a “rapid decomposition,” she said—an unusual pattern in other pneumonias. Other patterns seemed more particular to Detroit. “My back-of-the-envelope calculation is that obesity is probably a bigger deal than we gave it credit for, based on the Chinese data,” she said.

Awdish and her colleagues have spoken with doctors from Wuhan, China, which yielded some useful ideas about how to treat the disease, but Awdish also thought that there were limits to how directly the doctors’ experience could apply. She said, “What it means to be hypertensive or diabetic in Detroit, or in New Orleans or Chicago, means there is socioeconomic disadvantage, which makes it more difficult for patients to access care for chronic conditions, and means—not to overgeneralize—there is often an inability to keep yourself safe.” To protect yourself from the virus means sealing yourself off, but that is difficult if you have to keep working, or if there are too many people in too small a home, and it is hard to protect healthy family members from a sick one. Awdish said, “We’re all seeing cohorts of families come in.”

The intensifying outbreak in Detroit has a significance beyond its population numbers; it suggests what may be the pandemic’s second American phase. Abdul El-Sayed, a former public-health professor and Detroit health director—who ran a losing, progressive campaign for the Michigan governorship in 2018—pointed out that the first phase of the pandemic docked in coastal cities whose populations are comparatively young and healthy: Seattle, the Bay Area, New York, Boston. “You’re talking about a virus that spread from abroad, and so it’s going to be people who are more likely to have been abroad,” El-Sayed said. “But, once it seeds, it is going to be those people with the higher levels of underlying disease, who are most disconnected from institutions, who are most vulnerable.” El-Sayed noted that Detroit has the highest rate of infant mortality of any large city in the country. “Obviously, a coronavirus infection and a death before the age of one are two very different outcomes,” he said. “But, when you work upstream, the things that predict one event predict the other as well.”

As the virus crept inward from the coasts, epidemiologists began to regard the American South with special concern—in part because of resistance to social-distancing policies in some of those states, but especially because of underlying rates of disease in the region. Last week, a group of health researchers at Microsoft and the Dartmouth Atlas of Health Care project published an index of geographic risk from the virus which showed that the country’s most vulnerable areas, in large part, are places that COVID-19 has only just begun to touch: Florida, with its large elderly population, Appalachia, the South. Peter Hotez, the dean of tropical medicine at Baylor College of Medicine, in Houston, told me that he thought COVID-19 would become a “disparity disease,” which would follow the well-worn tracks of poverty, race, and comorbidity. Hotez said, “The point is, I think there’s going to be a Southern flavor to this before it’s over, and the Southern flavor is going to be high rates of diabetes and hypertension, which also occur in core cities like Detroit.” It has sometimes seemed like every American catastrophe in the past decade, once excavated, has turned out to be laid over an underlying structure of inequality, and to have adapted its contours. Maybe this one will, too.

The doctors in Detroit are in a fight against the disease, but they are also in a fight against this certainty. One slight advantage that they have over their counterparts in Seattle or New York is that it has taken a bit longer for the crisis to intensify in their city, and so they have been able to study it from afar before doing so from up close. Doctors are not always able to predict which patients will develop severe respiratory distress—there is so far no blood marker to track or telltale detail that shows up on a scan. “There are cases in our area where you are just not sure why this was the person,” Jeffrey Ditkoff, an emergency physician at Beaumont Hospital, in the suburb of Royal Oak, said. “And I think that’s where a lot of fear has broken out, because people don’t know why some young people are succumbing to this.” But in many cases there is a likely pattern. “The ones who have those comorbidities”—diabetes and heart and lung disease—“and obesity are the ones who aren’t responding as well to all of our measures before being put on a ventilator,” Ditkoff said. Healthier patients might stabilize with supplemental oxygen, which gives their bodies time to develop antibodies and fight off the virus, but the comorbid cases are less likely to respond.