As COVID cases are on the rise across the U.S., an internal memo from the CDC claims the Delta variant is equally contagious as chickenpox and may cause other illnesses.

The document, which was first obtained by The Washington Post, urges “the war has changed” and cautions states that fully vaccinated people may transmit the virus just as easily as the unvaccinated.

CDC director Dr. Rochelle Walensky has confirmed the authenticity of the document. Walensky says people should wear masks in “public, indoor settings” in areas of high levels of transmission.

The New York Times obtained a copy of the document that shows the Delta variant is more infectious than MERS, SARS, Ebola, the flu and the common cold, and as contagious as chickenpox.

The research in the document has been described as very concerning, declaring the Delta variant “is a serious threat” and requires immediate action, according to one federal official.

Walensky says the transmission of the Delta variant among vaccinated people “is worrisome and unfortunately warrants an update to our recommendations.”

Walensky recommends that everyone in schools, including students, staff and visitors, should wear a mask at all times. “The measures you need to get this under control are extreme” she said, calling it “one of the most transmittable viruses we know about.”

If a vaccinated person were to be infected with the Delta variant, they can just as easily infect someone else as a nonvaccinated person can.

“The bottom line is that, in contrast to the other variants, vaccinated people, even if they didn’t get sick, got infected and shed the virus at similar levels as unvaccinated people who got infected,” said Dr. Walter Orenstien.

The document indicates vaccinated people are safer and they reduce the risk of severe disease or death 10-fold and infection three-fold. However, 35,000 fully vaccinated Americans out of 162 million people who have been fully vaccinated may become infected every week.

The U.S. is averaging more than 66,900 daily cases over the past week. The average has risen sharply since the country hit a low of 11,299 cases in June, according to Johns Hopkins University.

“The number of cases we have now is higher than any number we had on any given day last summer,” Walensky said.

President Biden is stepping up his efforts to combat the virus as he is now mandating all federal employees receive the vaccine. “This is an American tragedy, people are dying who don’t have to die,” he said.