Rates of new Covid-19 cases in the United States are steadily dropping, suggesting the surge driven by the delta variant may have hit its peak—but some areas of the country are still struggling with high case rates, and the looming winter could lead to another surge in cases in some areas, experts say.

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Covid-19 case rates fall nationwide

According to data from Johns Hopkins University (JHU), the United States is currently experiencing about 72,000 Covid-19 cases per day, down 58% from a peak of 172,500 on Sept. 13. Meanwhile, reported Covid-19 deaths have dropped to about 1,400 per day, down from over 2,000 per day in late September.

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"We may be at a turning point," Marcus Plescia, CMO at the Association of State and Territorial Health Officials, said. "We have a lot more tools now to fight it."

Health experts attribute the drop to an increase in vaccinations and natural immunity from prior infections, as well as the return of precautions such as mask-wearing in some areas.

"It's a lot tougher for delta to hop from person to person because so many people were infected," Jason Salemi, an associate professor of epidemiology at the University of South Florida, said. "It just came at a considerable cost."

Some areas of the U.S. still struggling with high case loads

Even though nationwide Covid-19 case numbers are trending downward, some areas of the United States—especially regions with low vaccination rates—are still struggling with high case rates.

In Wyoming, where just 44% of the population is fully vaccinated, hospitals are still seeing surges of Covid-19 patients.

"In the 12 years I've been with the hospital, it's hands-down the busiest," Andy Dunn, a doctor at Wyoming Medical Center, said. "We're seeing more Covid patients, and we're seeing sicker Covid patients."

Utah, another state with a low vaccination rate, is seeing similar trends in its hospitals. "When a patient needs an ICU bed, it takes us two to three hours because they're all full," Angela Dunn, director of the Salt Lake County Health Department, said. "Usually, it takes 10 minutes."

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Even Vermont, a state that boasts the highest vaccination rate in the country, is experiencing Covid-19 surges in some pockets of the state. That could be in part due to waning immunity in many of the Vermonters who got vaccinated early, the Boston Globe reports.

"It could be our success in vaccinations has undermined our investment in other measures," such as masking, Tim Lahey, an infectious diseases physician and professor at the University of Vermont Medical Center, said.

What's next?

With the colder winter months on the horizon, some health experts say another surge of Covid-19 cases could be coming.

"The dark clouds on the horizon are obviously the holidays," Bruce Farber, chief of infectious disease at Northwell Health, said.

However, with a significant fraction of the population vaccinated and with vaccination rates slowly rising, any winter surge likely will be more muted than the one experienced last year, experts say.

"Personally, I'm optimistic that this may be one of the last major surges, and the reason for that is because so many people have been vaccinated, and also because a lot of people have had Covid," Arturo Casadevall, chair of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health, said. "We now have a lot of immunity in the population."

However, Covid-19 surges elsewhere in the world offer some reason for concern. According to the World Health Organization, worldwide Covid-19 case rates increased 4% last week, with Europe representing almost 57% of the total new cases.

"A lot of times, what we see in Europe is sort of the harbinger of what we see in the U.S. And so it concerns me that cases there are on the rise," Barbara Taylor, an assistant dean and associate professor of infectious diseases at the University of Texas Health Science Center, said.

There's also the possibility that a new variant could emerge. "The final potential threat or thing that worries us all is the ability of Covid to change and mutate," Taylor said. A new variant "could change everything about the pandemic over the next six months," she added.

However, Casadevall said he doesn't believe there's cause for concern in the United States just yet.

"In every single case that you see, there is a finite probability that a new variant will arise. So as long as you have the fire ongoing, it can happen," he said. "But if you get the numbers lower and lower, the likelihood of it happening is much lower." (Kamp/Abbott, Wall Street Journal, 10/31; Rattner/Towey, CNBC, 10/30; Hanna, CNN, 10/28; Stone, NPR, 11/1; Lazar, Boston Globe, 10/30)