The Wisconsin Department of Health Services last week new information about the newest variant of concern, variant B.1.617.2, also known as the Delta variant. Following the CDC’s recent classification update on June 14, DHS will begin reporting current case counts that are updated weekly, starting tomorrow, June 17. This strain was previously classified as a variant of interest, but has since been raised to a variant of concern. The CDC has established criteria for identifying variants that may be more worrisome than others. Variants are most commonly raised to variants of concern if they show evidence of being more contagious, causing more severe illness, or are more difficult to treat using known therapies. DHS, using CDC’s criteria, publicly reports on variants of concern.

To date, 26 cases of the Delta variant have been identified in Wisconsin since April 2021. Variants are identified through a process called whole genome sequencing. Whole genome sequencing takes a sample of the virus from a positive SARS-CoV-2 test specimen and reads its genetic code. DHS, the Wisconsin State Laboratory of Hygiene, and other laboratory partners regularly perform whole genome sequencing on a portion of positive tests.

"Wisconsin continues to report an increasing proportion of COVID-19 cases across the state that are variants of concern,” said DHS Secretary-designee Karen Timberlake. “We urge Wisconsinites to protect themselves, their families, and their communities by getting vaccinated. The sooner people get vaccinated against COVID-19, the less opportunity for the virus to keep mutating.”

The Delta variant was first discovered to be circulating in India in samples from October 2020, and has continued to spread to other parts of the world. It is attributed as the cause of a recent rise in cases in the U.K.

According to recent data, researchers believe the Delta variant spreads more rapidly and easily than the original strain of SARS-CoV-2. It is not yet known if this variant has any impact on disease severity. There is some evidence to suggest that therapeutics, such as monoclonal antibody treatments, may be less effective against this variant because of its unique mutations. Some laboratory studies have suggested that antibodies produced by the body in response to natural infection or a COVID-19 vaccine may be less effective at defending against the Delta variant virus than the original strain. The COVID-19 vaccines available in the U.S. have shown to provide some protection against the Delta variant.

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