The highly transmissible COVID-19 Delta variant, which was first discovered in October, is now responsible for the majority of all COVID-19 cases in the U.S., according to the Centers for Disease Control and Prevention (CDC).
During a Senate hearing on Tuesday, CDC director Dr. Rochelle Walensky said the variant is estimated to make up 83% of all sequenced COVID-19 cases in the country.
“This is a dramatic increase from up from 50%, the week of July 3,” Walensky said. She noted that fatalities stemming from the virus have risen by nearly 48% over the past week to an average of 239 per day.
“Each death is tragic and even more heartbreaking when we know that the majority of these deaths could be prevented with a simple, safe available vaccine,” she said.
Cases keep rising
The CDC said the Delta variant is circulating mainly in parts of the U.S. with low vaccination rates. Nearly two-thirds of the counties in the U.S. have vaccinated less than 40% of their residents, “allowing for the emergence and rapid spread of the highly transmissible delta variant,” Walensky said.
"In areas where vaccine coverage is low, cases and hospitalizations are starting to climb again," she said.
The Delta variant was first identified in India, but data from the World Health Organization (WHO) shows that it has since spread to more than 100 countries.
“The reason it’s so formidable is the fact that it has the capability of transmitting efficiently from human to human in an extraordinary manner, well beyond any of the other variants that we’ve experienced, up to now,” Dr. Anthony Fauci, medical advisor to the president, said during the hearing.