ST. PAUL — Yet another subvariant of COVID-19 is taking hold in Minnesota, raising concerns among public health officials at a time of year when rates of infection have typically been lower. So far, however, its effects remain to be seen.
As of early July, the BA.5 subvariant of the COVID-19 variant omicron has grown to become the dominant strain found in wastewater in the Twin Cities, according to data from the Metropolitan Council . The BA.5 and BA.4 variants, which are the most transmissible seen yet and can evade the immune system even if an individual has been infected by omicron before, now make up 80% of cases in the U.S., federal officials said Tuesday, July 12.
More than half a year after the omicron variant of COVID-19 first appeared in the U.S. and sent infection rates to record levels, its various offshoots have led to subsequent waves of infection.The growth in the variants prompted the White House to urge precautions such as masking and vaccine boosters.
The Minnesota Department of Health said the two variants have become more dominant in the state, and although the variants have grown, the number of COVID-19 cases in Minnesota has continued to trend downward since mid-May, according to numbers released July 5, the most recently available data from the state.
But Dr. Beth Thielen, an infectious disease physician at the University of Minnesota Medical School, warned that once-favored metrics such as infection rates don’t tell us as much as they did earlier in the pandemic.
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“We need to interpret those with caution, appreciating that this year as compared to last year, we have shifted to do a lot more testing that is outside traditional health care settings,” she explained. “With the rise in home testing, we are not catching the same proportion of cases that we did earlier in the pandemic.”
Public health officials and experts say as the amount of in-person laboratory-based testing for COVID-19 continues to drop, wastewater data from treatment plants has become one of the best ways to track infection trends. To track the BA.4 and BA.5 subvariants, they’ll continue to monitor wastewater and strain on hospitals and health care systems.
The University of Minnesota monitors wastewater from more than 40 treatment plants serving about two-thirds of the state’s population and was able to predict January’s surge of omicron cases based on the data.
While the impact on Minnesota health systems appears to remain stable despite the growth of BA.4 and BA.5, Thielen said it may be weeks before the variants’ effect on hospitals becomes noticeable. Hospitalization rates have dropped since mid-May, though the number of people in the hospital for COVID-19 has remained in the high 300s during that period.
Minnesota’s health department acknowledged that the rise in home testing means it won’t catch as many individual cases as it did in past years, and is instead focusing on keeping an eye on the impact on the health care system.
Still, in a statement the agency said it has more tools at its disposal to fight the virus than it did in the early days of the pandemic and said it is “well-positioned” to meet the challenge of BA.4 and BA.5. They say the public should look to the Centers for Disease Control and Prevention’s community risk levels for their area as a framework for what level of precaution to take.
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