New COVID BA2 subvariant increasing rapidly in Johnson County, across Iowa


HR King
May 29, 2001
With COVID-19 activity on the rise in Eastern Iowa as a result of a new coronavirus subvariant, a local public health expert is again emphasizing the importance of vaccinations and other safety measures to protect others.

Johnson County has seen elevated transmission rates and growing case counts in recent weeks as a result of BA.2, a subvariant of omicron that is rapidly spreading across the United States, according to Dr. Dan Diekema, epidemiologist and infectious disease specialist at the University of Iowa Hospitals and Clinics.

New infections in Johnson County have been on the rise over the past month, according to coronavirus data from the Iowa Department of Public Health.


On Wednesday, the county reported 174 new cases in the past week. That’s an increase from the 145 new cases reported last week, and the 114 cases the week before.

Fortunately, Diekema said, the rate of increase in the community is not as steep as it was during the omicron surge, which peaked in mid-January.

“I don’t think anyone expects it to reach anywhere near the levels of the (omicron) surge we saw back in January, and in part, that’s because the immune response from infection or from vaccination seems to be cross-protective between (omicron) and BA.2,” Diekema said.

He added, “So we are seeing an increase, but it’s not exponential. It’s of concern, but not at the same rate that we saw with (omicron).”

Over the past month, BA.2 has pulled ahead of other coronavirus variants in infection rates to now make up the vast majority — nearly 75 percent as of this past week — of all cases in the United States, according to U.S. Centers for Disease Control and Prevention.

In the region that includes Iowa, the omicron subvariant accounts for 78.8 percent of COVID-19 cases as of April 16, the latest data available from the CDC.

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Just three weeks ago, BA.2 made up just 34 percent of all cases in the region, highlighting how quickly this new subvariant has spread into the Midwest as well as other parts of the country.

This trend is also reflected across Iowa as state public health data shows new cases have been steadily increasing in recent weeks. On Wednesday, IDPH reported 1,063 new infections statewide from the past week, an increase from the 900 new cases reported last week.

Linn County is experiencing similar increases as Johnson County, with 129 new cases reported in the past seven days as of Wednesday. Last week, the county reported 103 new cases.

The reason?​

Omicron and its subvariants, including BA.2, have shorter incubation periods — or the time between infection and when symptoms begin. Some studies show symptoms can appear as little as three days after infection, whereas for previous variants, incubation periods were closer to five or six days.

In addition, waning immunity from previous infection and from vaccination could be another factor contributing to the recent increase. Vaccines and boosters are still highly effective against preventing serious illness, but Diekema said individuals are more likely to be infected the more time passes between the shots and exposure.

That’s why federal health officials recently approved a second COVID-19 booster dose for immunocompromised individuals and for those aged 50 and older.

Diekema also pointed to a change in community behavior as a driver of the recent increase, particularly as more Iowans feel comfortable being in indoor gatherings unmasked.

“When these new subvariants are introduced to those environments — close quarters, indoors without masks — spread can be very efficient,” he said. “ … I think a lot of this does have to do with lifting of mask requirements and just a general sense that this pandemic needs to be over.”

The effects of BA.2​

BA.2 and its other close cousins is no more severe than the omicron variant, which is also known as BA.1, Diekema said.

Experts nationwide have found an infection from the omicron variant of the coronavirus results in a milder illness than what was seen earlier in the pandemic. It’s unclear whether that’s a result of the makeup of the virus itself, or a combination of immunity that’s reducing severe outcomes, Diekema said.

Still, vulnerable populations — the elderly or immunocompromised — still face an elevated risk from an infection. There are more treatment options for infected individuals now, but Diekema said it’s still important these individuals receive their booster shots and are otherwise up-to-date on coronavirus vaccines.

Because of the high transmissibility of the virus, Iowa and the rest of the country did see an increase in hospitalizations during the omicron surge and an increase in deaths.

At the height of the omicron surge the week of Jan. 19, Iowa reported 991 patients hospitalized with COVID-19. By comparison, the number of patients hospitalized this week was 63 as of Wednesday.

“There certainly can be devastating consequences. Fortunately, it’s less common now with these omicron subvariants,” Diekema said.

As a result, UIHC officials and leaders at other hospitals are less worried about the possibility of their health care systems being overwhelmed by a spike in COVID-19 patients. Instead, they worry about their workforce, and the implications it could have for patients if an influx of workers call in sick during ongoing staffing shortages.