Delta variant is one of the most infectious respiratory diseases known, says CDC director

The delta Covid variant is one of the most infectious respiratory diseases scientists have ever seen, 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 strains that circulated previously,” CDC director Dr Rochelle Walensky told reporters in a briefing Thursday. “It is one of the most infectious respiratory viruses that we know of, and that I have seen in my 20 year career.”

The delta variant has spread rapidly in the United States, currently accounting for more than 83% of sequenced cases in the United States, up from 50% in 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 to about 3,500 per day, and deaths are also up 19% over the same period to about 240 per day.

“This virus has no incentive to let go, and it remains to find the next vulnerable person to infect,” Walensky said.

The virus is spreading in counties in the United States with low vaccination rates, while counties with high vaccination rates have lower rates of new cases.

Three states, Florida, Texas and Missouri, with low vaccination rates accounted for 40% of all new cases nationwide, White House Czar Jeff Zients told Covid. Florida alone accounted for one in five of all new cases in the United States for the second week in a row.

In hospitals nationwide, 97% of people admitted with symptoms of Covid are unvaccinated, and 99.5% of al Covid deaths are also among the unvaccinated.

Over the past week, the five states with the highest number of cases had higher rates of newly vaccinated people compared to the national average.

“We are at another pivotal moment in this pandemic, with a further increase in cases and with some hospitals reaching capacity in some areas, we need to come together as one nation,” Walensky said.