COVID map update reveals new states with "very high" wastewater activity

There are an increasing number of states across the U.S. where "very high" levels of the virus that causes COVID-19 are present in wastewater.

According to the U.S. Centers for Disease Control and Prevention (CDC), Idaho, New Mexico and South Dakota all had "very high" levels of the SARS-CoV-2 virus in their wastewater during the week between November 17 and November 23, 2024.

The week prior, between November 10 and November 16, only New Mexico's wastewater had this level of the virus present.

Arizona, Arkansas, Kentucky, Maine, Massachusetts and New Hampshire currently have "high" levels of COVID-19, while "moderate" levels were detected in Minnesota, Nebraska, Nevada, Oregon, Rhode Island, Utah and Wyoming.

Nineteen states had "low" levels, while 14 states and D.C. had "minimal" levels of the SARS-CoV-2 virus present in wastewater.

Between November 10 and November 16, "high" levels were detected in Arizona, Kentucky, Minnesota, Oklahoma, Pennsylvania and South Dakota, with "moderate" levels of the virus detected in Colorado, Idaho, Maine, Maryland, Ohio, Oregon, Rhode Island, Utah and Wyoming.

The data from New Hampshire, Mississippi, Oklahoma, and South Dakota all have limited coverage for the most current data, which means it is "based on a small segment (less than 5 percent) of the population and may not be representative of the state/territory," the CDC explains. Additionally, North Dakota has no data for this period.

The CDC monitors COVID-19 levels in wastewater as part of its surveillance strategy to track the spread of the virus in communities. Infected individuals shed the virus in their feces, meaning that monitoring wastewater can reveal increases in infection rates earlier than clinical testing or hospitalizations.

"The wastewater viral activity level indicates whether the amount of virus in the wastewater is minimal, low, moderate, high or very high. The wastewater viral activity levels may indicate the risk of infection in an area," the CDC said.

Wastewater data helps public health officials allocate resources and make informed decisions about mask and vaccination policies.

In the week ending November 23, about 4.5 percent of COVID-19 tests around the country came back positive. This represents a 0.3 percent increase from the week prior. Some regions had rates of up to 6.3 percent, such as Arkansas, Louisiana, New Mexico, Oklahoma and Texas.

"SARS-CoV-2, the virus that causes COVID-19, is constantly changing and accumulating mutations in its genetic code over time. New variants of SARS-CoV-2 are expected to continue to emerge. Some variants will emerge and disappear, while others will emerge and continue to spread and may replace previous variants," the CDC said in a statement.

Subvariant KP.3.1.1 made up 37 percent of COVID-19 variants in U.S. wastewater over the two weeks before November 23. The new XEC variant made up 24 percent, KP.3 made up 17 percent, JN.1 made up 8 percent and "other" made up 14 percent.

For the same period, variants detected in positive test samples were slightly different, with KP.3.1.1 making up 44 percent of recorded COVID infections, XEC totaling 38 percent and MC.1 composing 6 percent.

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