The so-called delta variant of the coronavirus now accounts for nearly 10 percent of new cases in the United States, the Centers for Disease Control and Prevention said Tuesday.
The agency on Monday declared the variant, which was first detected in India, a "variant of concern," a designation given when there is increased evidence of factors such as transmissibility or severity or reduced effectiveness of vaccines or treatments.
The change in classification "is based on mounting evidence that the Delta variant spreads more easily and causes more severe cases when compared to other variants, including B.1.1.7 (Alpha)," the CDC said in a statement to NBC News. The alpha variant was first detected in the United Kingdom, and in April, it became the dominant strain in the U.S.
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