COVID-19 levels in wastewater across Maine have largely remained flat in recent weeks, although several locations in northern Maine continue to report the highest concentration of the virus, corresponding to a recent increase in cases there.
Levels of COVID-19 found in wastewater throughout the state are much lower than a few months ago, according to the latest data reported by the Maine Center for Disease Control and Prevention and BioBot. However, after a steady decline in late January and the first half of February, virus concentrations have remained unchanged in recent weeks. More places in Aroostook County continue to see elevated virus levels.
Health authorities have touted wastewater testing as a useful tool for understanding levels of COVID-19 in communities, as the increased use of home testing has made other measures, such as the number of cases and positivity rates, less reliable. An increase in virus concentration in wastewater could serve as an “early warning” for an increase in cases, Maine CDC Director Nirav Shah said Tuesday.
Wastewater tests continue to paint the most troubling picture in Aroostook County, with locations in Presque Isle, Houlton and Fort Kent reporting higher concentrations of the virus than the rest of the state in recent weeks. It has also responded to higher infection rates – over the past week, Aroostook County has reported more than 300 virus cases per year. 100,000 people, almost three times higher than the statewide rate.
Outside the county, most Maine communities have experienced a significant decline in COVID-19 transmission since the rollout of wastewater tests was introduced in late January or early February. It has responded to a similar decline in reported cases and admissions.
But the decline appears to have leveled off in recent weeks, with wastewater districts in Maine’s largest municipalities reporting neither massive increases nor continued declines. In Bangor, which reported more than 2 million copies of the virus per liter of wastewater earlier this winter, the concentration has fluctuated between 200,000 and 350,000 in the last two weeks.
In Portland’s East End water district, concentrations have ranged from between 75,000 and 150,000 copies per year. liters in the last three weeks. It is a marked decrease compared to earlier in the winter, but the last few weeks have not shown a continued decrease.
Nationwide, a Bloomberg News analysis of wastewater test data maintained by the U.S. Centers for Disease Control and Prevention found that the concentration of virus in wastewater increased significantly in about one-third of the counties counted.