Are Utah communities with high vaccination rates actually seeing the fewest coronavirus cases?

Only now, as more people are fully protected, is a link becoming more consistent. And there are still exceptions.

(Francisco Kjolseth | The Salt Lake Tribune) In Park City, people lined up for COVID-19 vaccine on March 18, 2021, at Utah Film Studios. While Park City consistently has had the highest vaccination rates in the state, it — until recently — still had one of the worst infection rates in Utah.

Nearly six months after coronavirus vaccines became available to the public, the Utah communities with the highest vaccination rates are now showing some of the state’s lowest rates of infections.

But this wasn’t always the case. Only six weeks ago, Park City — which consistently has had among the highest vaccination rates in the state — still reported one of the worst infection rates in Utah.

Just a month ago, eastern Summit County had the state’s fourth worst infection rate despite having the 11th highest vaccination rate of Utah’s 99 “small areas,” used by state officials to study local health trends.

And nearly all of eastern Salt Lake County was classified as having “high” coronavirus transmission rates, despite being part of a continuous stretch of cities and neighborhoods where more than half of residents were at least partially vaccinated.

But one dose isn’t the same as two doses.

And now that more people are fully protected from the coronavirus, the link between lower case rates and higher vaccination rates is far more consistent.

As of last week, nearly every Utah community with more than half of its residents fully vaccinated had seen its 14-day rate of new cases fall below the “high” transmission category, of at least 100 cases per 100,000 people.

(Christopher Cherrington | The Salt Lake Tribune)

“We would of course expect that as more people are vaccinated in a community, that we will see fewer and fewer cases of COVID-19,” said Jenny Johnson, spokeswoman for the Utah Department of Health.

Of the nine communities where a majority was vaccinated, only one remained at a “high” transmission rate: Downtown Salt Lake City.

But even there, the cases were quite a bit different than they used to be, said Ilene Risk, epidemiologist for Salt Lake County.

Of the new cases in the past two weeks, Risk said, “almost all of them have a known exposure.” Most of them occurred within just a few households, with two people contracting the virus at a homeless shelter and one at a school.

If the source of exposure were not known, Risk said, it would “indicate a higher level of community transmission going on that we’re not aware of.”

None of the new cases in downtown Salt Lake City were “breakthrough” cases, she noted, which are infections that occur after a person has been fully vaccinated. And the largest share of the patients were between ages 30 and 50 — meaning they are eligible for vaccines.

“It’s just a nudge to get vaccinated,” she said.

Not all communities with low case rates have high vaccination rates, though. North Logan had the state’s lowest infection rate, despite only 38% of residents being fully vaccinated — which is about average for Utah.

Grand County still has the state’s worst infection rate, even though 48% of residents are fully vaccinated — well above the national average of 40%.

And the Nephi-Mona area of central Utah had fallen below the “high” transmission rate, even though it had the state’s lowest vaccination rate, at just 22%.

Health experts have said about 80% of residents would need to be protected from the virus to reach herd immunity.