Not all Covid waves look the same. Here’s a snapshot of the Delta surge

At first, Joyce Dombrouski thought it might just be some kind of blip. Maybe it was Montana’s summer tourists. But then, at one point this August, St. Patrick Hospital in Missoula had 30-plus Covid inpatients — “and we thought 30, a year ago, was a horrific number,” said Dombrouski, the chief executive of Providence Montana.

It just kept growing. Three or four admissions a day, then five or six, then seven. The hospital was nearing capacity. There were more Covid patients in the ICU than the team had seen before, and they tended to be younger now. “Our median age has dropped to the mid-40s, and at the start of the pandemic, it was between 70 to 80,” Dombrouski went on. Then, her team got a call from Oklahoma, three wide western states away, asking if St. Patrick could take a transfer patient.

Waves of Covid can give you an awful sense of déjà vu. As “Hot Vax Summer” gave way early to Delta-anxious fall, you could be forgiven for feeling a familiar sense of dread, not so different from what you’d felt before the dismal winter of 2020 or the Southern surge that took off that July.

But not all spikes are created equal. The Delta-caused wave that now seems to be sloping downward has different demographics than previous waves, and provides a snapshot of the current state of the pandemic in the United States. While racial and ethnic disparities in Covid cases and deaths persist, some appear to have narrowed to a certain extent. Meanwhile, other divides in who’s getting seriously ill — rooted in geography, in vaccination status — seem to have grown, and epidemiologists don’t think those two trends are unrelated.

Being unvaccinated is the risk factor for hospitalization and death that public health experts emphasize most. Dombrouski said that about 90% of St. Patrick’s hospitalized Covid patients haven’t been immunized. That gap is just as obvious in national data from the Centers for Disease Control and Prevention, which showed that unvaccinated adults were hospitalized for Covid at a rate 12 times higher than the fully vaccinated.

To epidemiologists, that’s also one of the primary reasons for the age difference Dombrouski noticed: Lower vaccine coverage in younger age groups likely tugged down the average age of the sickest Covid patients. The CDC data show the proportion of hospitalized patients aged 18-49 increased from 25% pre-Delta to 36% amid the surge. Vaccination affected infection numbers more generally, too. While severe cases are uncommon in kids, the fact that they’ve become eligible for immunization later meant they began to account for a greater slice of new infections during the Delta wave than they had at the start of the pandemic.

Even though the shots’ ability to prevent coronavirus transmission was reduced by Delta, they remain remarkably good at preventing severe disease and death. For people who aren’t immunized, explained Naor Bar-Zeev, deputy director of Johns Hopkins’ International Vaccine Access Center, “the fact that the community around them is vaccinated is now less helpful than they might otherwise have been.”

That effect is only amplified by the country’s divisions. Vaccine hesitancy is a social phenomenon, and a shared suspicion ends up creating pockets of elevated risk, as Dombrouski saw in Montana.

“We’re seeing this kind of percolation of the virus, flaring up in unvaccinated networks, and then trickling through the vaccinated ones,” said Bill Hanage, an epidemiologist at Harvard’s T.H. Chan School of Public Health. “I’m saying ‘networks’ there quite deliberately, because we don’t have random mixing. You know, unvaccinated people tend to hang out with each other. And that means that you’ve got sort of stuttering transmission chains, which occasionally blow up.”

To Bar-Zeev, bridging those divides is paramount in order to make headway against Covid-19. “We’re not at a point where we can say, ‘There’s kooky weirdos who don’t get vaccinated.’ This is your mums and dads, your normal people in the community,” he said. Their concerns need to be addressed seriously and respectfully, he added: “We have to engage with them. They are the bread and butter of America.”

Throughout the pandemic, perhaps the clearest message written in death statistics was the profound health inequality of this country — how racism and economic insecurity become absorbed into bodies in the form of exposure risks and comorbidities, unfair access to care as American as apple pie. If you adjust the statistics to take into account the different distribution of ages in different ethnic and racial groups, Black, Hispanic, and American Indian, and Alaska Native people were all at least twice as likely as white people to die of Covid between March 2020 and August 2021, according to a Kaiser Family Foundation report using CDC data.

The gaps between various groups have fluctuated during the pandemic. Disparities tended to balloon as overall death and case rates rose, and then to flatten a bit as those general curves came down. Some of those disparities remained striking during the Delta wave: American Indian and Alaska Native communities have continued to experience some of the highest death rates of any group — a testament to the health impacts of colonialism and its long legacy of inequality. But for some groups, that pattern of disparities rising along with national Covid numbers appears to have shifted a bit.

“As we began to move into August and early September this year, which reflect the arrival of the Delta variant, we saw an increase in death rates, but the death rates for Black and Hispanic people remained similar to the rates for white people,” explained Latoya Hill, a senior policy analyst at the Kaiser Family Foundation, and one of the authors of the report.

There are some asterisks to keep in mind. Those recent statistics are not adjusted for the age distributions of those different groups, and the underlying structures that have created the disparities in the first place have not gone away. But Hill and her colleagues see some interesting hypotheses in those data.

“There’s likely a variety of factors contributing to this narrowing in disparities over time, including a decreasing gap in the vaccination rate across the country,” she said. Part of that effect may also have to do with reopening. Early in the pandemic, much of the risk was borne by essential workers, who are more likely to be people of color. But as stay-at-home orders lifted and many began interacting more, those who’d previously been sheltered may have been more susceptible to infection.

Geography may be a factor, too. “There actually has been a higher death rate in rural parts of the country in recent periods compared to early in the pandemic,” Hill said — and rural places are often whiter.

There seems to be a kind of perfect storm in some of those less populous places, greater suspicion of government recommendations dovetailing with the dynamics of where a variant happens to reach at what point. Some of the highest rates of vaccine hesitancy are in states of the mountain west, like Wyoming, pointed out Cecile Viboud, an epidemiologist at the National Institutes of Health’s Fogarty International Center. “They’ve also been a little bit late with this pandemic in the arrival of the different waves, and that’s true of the Delta wave as well,” she said — and what’s late in going up will be late in coming down, as we’ve seen recently.

Those rural surges come with challenges all their own. Often, small, local hospitals don’t have the equipment, staffing, or experience to take care of people so sick. “Some of them, you know, don’t have a respiratory therapist in house at night, or don’t have intensive care doctors,” said Robert Stansbury, an associate professor of pulmonary critical care, and sleep medicine at West Virginia University. “I have one very vivid memory of FaceTiming this doctor at two o’clock in the morning, and he’s like, ‘You know, this is the first vented patient I’ve taken care of in 20 years,’ and he was holding his phone up so I could see the waveform on the ventilator to try and help troubleshoot some issues.”

For Stansbury, it’s a relief to see Covid admissions at his hospital dropping dramatically. Why the decrease? “There’s a lot of conjecture,” he said. “I mean, I think more people are getting vaccinated. Like, that’s one. And I think a lot of the unvaccinated population either got Covid and have some natural immunity, or unfortunately passed from Covid.”

To Viboud, a central question is how well different kinds of immunity will hold up over time. “What the modeling world and we and others have been doing suggests that there’s a good level of immunity in the population, and that’s really what made the Delta wave come down finally,” she said. “That immunity is primarily through vaccination, but also through natural infections.” She’s optimistic about the next few months — provided they don’t bring the emergence of another, even less controllable variant.