In the U.S., 59.72% of counties are reporting high community transmission. Five weeks ago, only 8% of counties were reporting high transmission, according to federal data.

Louisiana now has the highest case rate in the country with more than 600 new cases per 100,000 residents, according to federal data.

Louisiana Gov. John Bel Edwards on Monday reinstated a statewide indoor mask mandate for everyone ages 5 and above.

Louisiana is followed by Florida, Arkansas and Mississippi with 500, 400 and 300 new cases per 100,000 residents respectively.

-ABC News’ Arielle Mitropoulos

Sen. Lindsey Graham, who is vaccinated, said he’s tested positive for COVID-19.

"I started having flu-like symptoms Saturday night and went to the doctor this morning," the Republican senator tweeted Monday. "I feel like I have a sinus infection and at present time I have mild symptoms."

Graham continued, "I am very glad I was vaccinated because without vaccination I am certain I would not feel as well as I do now. My symptoms would be far worse."

In Louisiana, which has the nation's highest case rate per 100,000 residents, COVID-19 hospitalizations are reaching peak levels, with more than 1,700 patients now receiving care.

"We're seeing people that are way too young to be so sick," David Wrightson, a respiratory therapist and ECMO (extracorporeal membrane oxygenation) specialist for the Willis-Knighton Health System in Shreveport, Louisiana, told ABC News. "We see families destroyed. We see children without one or more parent because of this virus. We see a new mom who will never go home to see her newborn, will never see her child grow up."

He went on, "When you see someone that's 30 years old with no medical problems at all, nobody knew anything was wrong, and we have this person literally on death's doorstep, doing everything in our power to turn them around and return them to their family. The vaccine is something worth getting."

More people need to see and understand the reality of this disease, he said.

"I wish I could show them a few steps in our day to see what we see and to see what we have to do, and to go home at night and, and have nightmares about those things, and sometimes cry yourself to sleep," he said.

-ABC News’ Erica Baumgart and Arielle Mitropoulos

Denver is mandating vaccinations for city employees and those in high-risk jobs like first responders, correctional workers and school personnel. The mandate also applies to staff at long-term care facilities, shelters and hospitals.

As the COVID-19 delta variant causes a surge in COVID-19 cases and hospitalizations in the U.S., protests against mandatory COVID vaccines have cropped up around the country.

Dozens of people gathered outside St. John's Hospital in Maplewood, Minnesota on Saturday to protest vaccination mandates from health care systems including M Health Fairview, Allina Health, HealthPartners and Children's Minnesota,
ABC affiliate KSTP reported.

The only exemptions are for strong religious beliefs or medical conditions. "We stand up for our patients all the time and no one's standing up for us," Allison Todd, a nurse at Allina Health's Cambridge clinic told the station.

Hundreds protested outside of ChristianaCare in Newark, Delaware, Saturday to push back against the hospital's decision to mandate the COVID-19 vaccine for all employees, according to WPVI.

And more than 100 gathered in Vancouver, Washington, to protest COVID-19 vaccine mandates for hospital workers, ABC's Portland affiliate, KATU reported.