After months of declines, the levels of COVID-19 detected in Twin Cities wastewater samples has risen according to the latest data.
The Metropolitan Council on Friday released its latest wastewater sample data for the dates Sept. 6-12, which showed the viral load of COVID-19 entering its wastewater treatment plant increasing by 36% compared to a week earlier.
The viral load of the omicron subvariant BA.5 rose by the same amount, and constitutes 90% of the the total found in wastewater samples taken during the period.
For the first time too, the Met Council says it's beginning to see levels of another omicron subvariant, BA.2.75, in samples, but at this time it comprises only 1-2% of the total.
BA.2.75, which was discovered in India in the spring, has not yet been designated as a variant of concern by the World Health Organization, with the omicron subvariants BA.4 and BA.5 still dominant.
The rise in COVID levels came in the days that followed the return to school in Minnesota.
In the past two years, the return to school and the onset of fall and winter has brought with it rises in COVID-19 cases, first with the alpha variant in fall/winter 2020, and then with the delta and then the original omicron variant in fall/winter 2021.
Unlike last year, there are no cities or counties left in the state that have mask mandates, which could impact the spread in schools and elsewhere this fall and winter.
At the same time though, there is likely greater immunity built up due to past vaccinations, boosters, and the number of people who have previously had the virus in Minnesota compared to last year.
There is now a bivalent booster targeting the BA.4 and BA.5 subvariants of COVID available in Minnesota.
Gov. Tim Walz got his shot on Friday, and urged other Minnesotans to do the same, saying it's the best defense to prevent a surge of hospitalizations this fall.