North Dakota at or near omicron peak, wastewater and forecasts show
COVID-19 testing and analyses of wastewater samples from cities around North Dakota indicate the omicron wave is at or near a peak, although trends vary around the state.
FARGO — The omicron wave now surging in North Dakota appears to be slowing and might be at or approaching a peak as the trajectory of the coronavirus spread behaves unevenly throughout the state.
That’s the conclusion of a top analyst for the North Dakota Department of Health, who has examined COVID-19 test results, projection models as well as wastewater monitoring samples from around the state.
Given the mixed picture, epidemiologist Grace Njau is reluctant to declare that North Dakota has reached a peak in the omicron wave, but wastewater data combined with other forecasting models indicates the state is at or near its omicron apex. Some cities are likely already there.
Samples drawn from wastewater show the pandemic’s omicron wave is declining in some eastern cities, including Fargo, but still rising or beginning to level off in western cities, including Williston and Minot.
The virus levels in wastewater throughout Cass County, including West Fargo and Casselton and Horace as well as Fargo, are definitely falling, said John McEvoy, professor and chairman of microbiology at North Dakota State University, which has been conducting the wastewater testing.
“They’re actually dropping pretty fast,” he said, noting that the peak in Fargo appears to have happened in mid-January.
“Cass County is definitely looking better, and I would say some other locations are maybe just a little bit behind,” including Grand Forks, which is beginning to improve, McEvoy said.
In Bismarck-Mandan, “It’s coming down a little bit,” he said. “The latest number for Bismarck was low. Don’t read too much into it yet.” In neighboring Mandan, “It’s more leveling off.”
It appears cities in eastern North Dakota are ahead of cities in the west in seeing the omicron wave subside, McEvoy said. The NDSU microbiology lab is analyzing wastewater samples from almost 20 cities around the state.
“Jamestown now is starting to turn, because we have lower numbers there,” he said. Valley City often moves in tandem with Jamestown, but the lab has fewer samples from Valley City, so a clear trend there isn’t evident.
Watford City, which got “slammed” by the earlier delta wave, hasn’t seen a significant increase in virus levels during the omicron surge, McEvoy said.
“There really hasn’t been an omicron wave in Watford City to speak of,” he said. “The numbers have not gone up appreciatively.”
Nearby Williston, however, has seen an omicron spike, but appears to be on the cusp of a turn, McEvoy said.
In general, he added, “The overall message, I think it’s encouraging how quickly it’s dropping off. It’s clearly more hopeful.”
The stark differences between various regions of the state is likely due to vaccination rates, which are much higher in eastern North Dakota, and population, as the highly contagious omicron variant is rapidly spreading through larger cities, Njau said.
For example, the prevalence of the coronavirus has been consistently declining in Fargo for the last few weeks, meaning it’s likely North Dakota’s most populous city has hit its omicron peak.
“In Fargo, with just the way that omicron transmitted so fast within that population, it is quite likely that we’re seeing a true reflection of a decrease in cases,” Njau said.
The NDSU lab has used genetic sequencing to identify coronavirus variants in wastewater samples since March 2020. The testing is very sensitive in detecting fluctuations in virus levels, and appears to pick up even one or two cases in smaller cities, McEvoy said.
Unlike testing, the wastewater monitoring provides a community-wide picture, since it analyzes all viruses shed into the wastewater system, he said. “You’re getting a snapshot of the community,” although the method does not determine the number of cases.
In contrast to positive test results in North Dakota, wastewater data is able to provide a fuller picture of the coronavirus’ prevalence statewide because it gathers information from people who do not get tested or who conduct at-home testing, Njau said. Positive at-home tests do not need to be reported to the Department of Health.
Weekly COVID-19 case forecasting by the Centers for Disease Control and Prevention predicts North Dakota will reach a peak in cases in about two weeks, and infections will sharply decline in the weeks following.
Last week, North Dakota reported a pandemic high of 12,042 active COVID-19 cases. As of Thursday, Jan. 27, the state’s 14-day rolling positivity rate was nearly 20%, according to Department of Health data.