The delta coronavirus variant now accounts for 83 percent of virus samples analyzed in the U.S., CDC Director Rochelle Wallensky, MD, said July 20, according to The Wall Street Journal.
In the week ending July 3, delta accounted for 50 percent of all cases, Dr. Walensky said in testimony before the Senate Committee on Health, Education, Labor and Pensions.
"This is a dramatic increase," she said. "In some parts of the country, the percentage is even higher, particularly in areas of low vaccination rates."
In nearly two-thirds of U.S. counties, the vaccination rate is under 40 percent, according to Dr. Walensky. As of July 20, 48.7 percent of the U.S. population was fully vaccinated, CDC data shows. Among U.S. adults, 68.3 percent have received at least one dose, and 59.6 percent were fully vaccinated.