Being able to detect coronavirus in wastewater has been a helpful tool and oftentimes a useful predictor for how the pandemic will evolve, and the latest data from the Metropolitan Council shows a continued decrease from the omicron-fueled spike during December and January.
But the latest samplings also show minimal levels of the omicron sub-variant, known as BA.2. The sub-variant is thought to be 1.5 times more transmissible than the original omicron strain (BA.1), though it may not be as efficient at spreading.
“I think it’s important to note that while case numbers of BA.2 are increasing, they’re not increasing anywhere close to the way that the BA.1 cases increased,” said Dr. Andy Pekosz, professor and virologist with Johns Hopkins’ Bloomberg School of Public Health, in an interview this week with WTOP News.
Wastewater samples show that 2.7% of all samples studied in the seven-county metro area of the Twin Cities have been identified as BA.2, while more than 96% remain BA.1 (the original omicron). The data reflects the most recent 7-day period, which was the 7-day period ending Feb. 14.
The virus is tracked in wastewater by copies of viral RNA per milliliter. And the number of copies per milliliter tends to correspond with the number of cases in the metro per 100,000 people.
The Met Council was tracking a pandemic-high 965 copies per milliliter of omicron BA.1 on Jan. 5, which represented the peak of the omicron wave. As of Feb. 14, the omicron BA.1 variant has been detected in only 31 copies per milliliter.
The sub-variant is even less prevalent, with only 2 copies per milliliter detected. What's more is that BA.2 was actually first detected Jan. 8, according to Met Council data, and hasn't shot up in the six weeks since.
Overall, the Met Council hasn't detected levels of coronavirus in wastewater as low as they are now since mid-July.