COVID-19 viral load up 3% in Twin Cities wastewater

The COVID-19 viral load in Twin Cities wastewater increased 3% over the past week ahead of the July 4 holiday.

While small, it was the second straight increase in the amount of viral material found in sewage at the Metropolitan Wastewater Treatment Plant in St. Paul. Levels remained five times lower than they were during the January peak of Minnesota's winter omicron COVID-19 wave, though.

COVID-19 hospitalizations in Minnesota also rose back above 400 late this week after declining to a low of 361 on June 18. Many of the 401 COVID-19 hospitalizations on Thursday involved people who had been admitted for other purposes and only discovered their infections upon routine screening. But the total included 41 people receiving intensive care, up from 26 five days earlier.

July has been a low-point in COVID-19 activity over the past two-plus years of the pandemic, but it also marked the start of gradual increases. In 2020, health officials were closely monitoring summer outbreaks in bars and group settings as sources of transmission. In 2021, the state encountered a fast-spreading delta coronavirus variant that spread quickly and by fall was causing a higher rate of severe illness among younger, unvaccinated adults.

Health officials are confident that Minnesota is better positioned against COVID-19 this summer with strong supplies of antiviral treatments and high rates of immunity through recent infections and vaccinations. However, apathy is a concern. Only 48% of Minnesota's most vulnerable seniors are up to date with COVID-19 vaccinations, meaning they have received the initial doses plus boosters when recommended.

"We have more tools available to us now to manage this disease with vaccination, testing, medications, which helps put us in a better spot, but we need people to continue to take those actions," said Kathy Como-Sabetti, COVID-19 epidemiology section manager for the Minnesota Department of Health.

The state this week joined others in switching to weekly rather than daily reporting of COVID-19 activity. Thursday's first weekly update showed declines in the seven-day average of new infections and COVID-19 deaths through late June. Total COVID-19 deaths in Minnesota reached 12,806.

At-home COVID-19 tests have grown in popularity and aren't included in public case numbers. As a result, wastewater testing has emerged as a more stable indicator of COVID-19 risk in the community.

Viral levels were scattered this week among 40 wastewater plants reporting their results to the University of Minnesota. They changed little across most of the state in the week ending June 26, but increased slightly in the southwestern and south-central regions.

Sampling at the St. Paul plant showed that a BA.5 subvariant of the coronavirus was now the largest source of COVID-19 material in Twin Cities wastewater. It made up 43% of the viral material found over the past week.

All Minnesota counties were designated last week by the Centers for Disease Control and Prevention with low COVID-19 levels that presented little threat to their local hospital capacities.

Those numbers fluctuate from week to week, though, especially in smaller and rural counties. On Thursday, the CDC put Twin Cities counties back at moderate risk and nine Greater Minnesota counties — Carlton, Cook, Itasca, Koochiching, Olmsted, Redwood, Renville, Rock and St. Louis — at high risk.