Utah’s lull is over. Here’s where COVID-19 cases are spiking yet again.

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A month ago, health experts thought Utah might have seen the worst of its autumn surge of the coronavirus. Cases were declining and hospitalizations were beginning to plateau.

But since mid-October, case counts have been rising rapidly again, driven by new outbreaks in some of Utah’s less-vaccinated, rural communities.

Nearly 1 in 59 residents of Carbon County and 1 in 63 residents of Emery County tested positive in the past two weeks, according to Thursday data from the Utah Department of Health. Rates weren’t much lower in Box Elder, Morgan, and Tooele counties.

In eight communities, more than 1 in every 100 residents have tested positive in the past two weeks. Six of those areas posted vaccination rates of less than 45 percent: rural Box Elder County, Tremonton, Carbon County, Emery County, rural Tooele County and the Tooele Valley.

The seventh, Morgan County, reports that 45.3% of its residents are fully vaccinated. That leaves only one of the eight — Brigham City — with more than half of its residents (50.2%) fully vaccinated.

In Salt Lake County, over the last two weeks, the rolling seven-day average of new COVID-19 cases has risen from 399 per day on Oct. 14 to 497 per day on Oct. 27, according to the county health department’s data.

Its 14-day case rate is 559.3 cases per 100,000 people — or one out of every 179 people. Salt Lake County also boasts 59.5% of its people are fully vaccinated, a higher percentage than the less-populated communities with the highest case rates.

Southeast Utah provides an apt example of the effect of vaccination rates, said Bradon Bradford, director of the health department that oversees the three counties.

Grand County — whose tourist center of Moab has made it a COVID-19 hotspot on and off during the pandemic — reported less than half of the cases per capita than neighboring Emery and Carbon counties, which have the worst rates in the state.

In Carbon and Emery counties, “the rate of fully vaccinated people is just not incredibly high,” Bradford said.

Among those eligible to get a COVID-19 vaccination, 50.76% of Carbon County residents, and 48.25% of Emery County residents, are fully vaccinated, according to the Southeast Utah Health Department’s dashboard.

In contrast, Grand County has 68.5% of its eligible population fully vaccinated. Grand County also has a mask mandate in place, Bradford noted.

“Grand County is doing much better than Carbon County and Emery County,” Bradford said. “Certainly, we don’t think of it as an experiment, but realistically, there’s a lot to be gleaned from what’s happening in our different counties.”

Natural immunity does not appear to account for Grand County’s advantage in the recent surge. While influxes in tourists have led to sharp spikes in cases there, overall, since the pandemic began, a slightly smaller percentage of its residents have tested positive than in Emery or Carbon counties.

Castleview Hospital in Price recently issued a letter, “basically a plea for help to the community,” Bradford said. The letter, signed by hospital CEO Greg Cook, urged residents of Carbon and Emery counties “to seriously consider getting vaccinated,” as well as to wear masks indoors in large groups, and maintain social distance. Cook also advised people not to delay emergency care.

The uptick in hospitalizations, Bradford said, “is putting a strain on a lot of their supply chain, oxygen in particular. They’re going through a lot of oxygen. And the whole situation, as we hear from throughout the country, is really wearing on their staff.”

Bradford said his department has heard “from people who have close friends or relatives that are impacted by COVID, and in a serious way, and still continue think that it’s not going to reach out and touch their lives. Either they don’t think they’re going to get exposed, or they don’t think they’re going to get sick. So they don’t access this very miraculous vaccine.”

Case rates also were exceptionally high in Box Elder County, where vaccination rates ranged from 34% in Tremonton to 50% in Brigham City.

But low vaccination rates aren’t the only reason for the case spikes in Box Elder County, said Estee Hunt, spokeswoman for the Bear River Health Department. Hunt said poor access to COVID-19 testing is one factor, because that means people are more likely to go out in public without knowing whether they are carrying the coronavirus.

Also, Hunt said, the county has seen a number of outbreaks in elementary schools in recent weeks.

[Read more: ‘It’s real’: Utah doctors and nurses talk about treating kids sick and dying from COVID-19]

Not all communities with low vaccination rates are reporting the state’s highest case rates. While transmission levels are deemed “very high” statewide, case rates were below 1 in 250 residents in six of Utah’s 99 “small areas.” Health officials use the small-area data to track local health trends.

In those six communities with low case rates, three reported less than half of residents were fully vaccinated: Provo, near Brigham Young University and east of city center, and Hurricane and La Verkin.

The other three spots with low case rates were Park City, Cottonwood Heights and the west side of Orem.

But none of the state’s most-vaccinated communities reported anything close to the state’s highest case rates.

Of 20 communities that are more than 60% vaccinated, only one — Midvale — reported new cases for more than 1 in 150 residents. Nearly all of the rest reported new cases in less than 1 in 175 residents.

The Bear River Health Department, Hunt said, is ramping up testing in Box Elder County. The department recently began offering testing every day of the week in Brigham City, and four days per week in Tremonton.

Hunt said her department is preparing to distribute at-home coronavirus testing kits, to help vulnerable populations who may not be able to get to a testing site.

In Carbon and Emery counties, Bradford said his department has increased availability of testing, “so we can hope to overcome this current surge.”