The Dean of the School of Public Health at Brown University warned of the tough months ahead in the US due to Covid, as new data shows that people infected with the Delta strain are up to 1,000 times more likely to get viruses in may wear their nasal passages than those who are infected with the original strain.

“I think people are underestimating how bad this is going to be,” said Dr. Ashish Jha. “We have a very tough August ahead of us, probably a very tough September before that really changes.”

Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, told reporters at a briefing Thursday that the Delta variant is “one of the most contagious respiratory viruses we know and have seen in my 20-year career” .

Jha told CNBC The News with Shepard Smith that the infection rate could be worse in winter and predicted the delta peak could peak within two months.

“It could peak in September, but we are far from peak. Right now we are doing 40,000 cases a day, it will go a lot higher before it peak,” Jha said.

The delta variant has spread rapidly in the US and currently accounts for more than 83% of the cases sequenced in the US, up from 50% in the week of July 3, according to the CDC.