The delta Covid variant is one of the most infectious respiratory diseases ever seen by scientists, the director of the Centers for Disease Control and Prevention said Thursday.
The variant is highly contagious, largely because people infected with the delta strain can carry up to 1,000 times more virus in their nasal passages than those infected with the original strain, according to new data.
"The delta variant is more aggressive and much more transmissible than previously circulating strains," CDC Director Dr. Rochelle Walensky told reporters at a briefing Thursday. "It is one of the most infectious respiratory viruses we know of, and that I have seen in my 20 year career."
The delta variant has spread quickly through the U.S., accounting for more than 83% of sequenced cases in the U.S. right now, up from 50% the week of July 3.
The seven-day average of new cases is up about 53% from last week, currently at 37,674 new cases per day. Hospitalizations are up 32% from last week at about 3,500 per day and deaths have also increased 19% in the same time frame to about 240 per day.Chart shows current data on Covid-