COVID-19 updates: More than 10,000 new deaths reported in US in 1 week

Nearly all of those hospitalized with COVID-19 in the U.S. are unvaccinated, according to government officials and frontline health care workers.

CDC Director Dr. Rochelle Walensky said last week “well over 90% of people who are in the hospital are unvaccinated.”

“Those who were unvaccinated were about four-and-a-half times more likely to get COVID-19, are 10 times more likely to be hospitalized, and 11 times more likely to die,” she added. 

Hospitals across the nation contacted by ABC News have echoed Walensky’s statement. 

At Saint Alphonsus Regional Medical Center in Boise, Idaho, doctors said about every COVID-19 patient in their overflowing ICU was unvaccinated. 

“We are overwhelmed,” the ICU director said. “We have so many patients with COVID who are unvaccinated.”

Tracking hospitalizations by vaccination status is tough because only about half the states report that information and many share it in different ways. 

However, an analysis of that data found that breakthrough cases in general are uncommon among the fully vaccinated and “the vast majority of reported COVID-19 cases, hospitalizations and deaths in the U.S. are among those who are unvaccinated or not fully vaccinated,” according to a study released last month by The Kaiser Family Foundation, a nonprofit focused on national health issues.

-ABC News’ Arielle Mitropoulos, Sony Salzman and Brian Hartman

Russian President Vladimir Putin said he will self-isolate "for a certain period," after a member of his entourage tested positive for COVID-19.

Putin made the comment during a telephone call with Tajikistan's president, while excusing himself from attending a regional summit there this week, the Kremlin said Tuesday in a readout of the call.

Putin's spokesman, Dmitry Peskov, said the Russian leader is "completely healthy" and that the self-isolation will not affect his work. Putin will continue to participate in meetings via video but will not meet with people in person while he self-isolates.

Since the start of the coronavirus pandemic, Putin has effectively been in a form of isolation, with most people being required to quarantine in a hotel for 10 days before meeting with him.

Putin hinted at the issue of COVID-19 among his inner circle on Monday but still went to several public events, including a meeting with Russian Paralympians, attending military exercises conducted in coordination with Belarus and a meeting with Syria's president.

"Even in my entourage, problems are arising with this COVID. We need to sort out what is happening there really," Putin said while meeting with the Paralympians. "I think I, myself, will soon have to go into quarantine. A lot of people are sick around [me]."

Putin's self-isolation has prompted speculation that he may be using it as a convenient excuse to not attend the summit in ex-Soviet Tajikistan in person. Chinese President Xi Jingping has also dropped out of the summit.

-ABC News' Patrick Reevell

The superintendent of schools in Lee County, Florida, informed parents and staff Monday night that he is reversing the mask mandate he imposed for students and will now let parents opt their children out of wearing face coverings.

In a letter, the superintendent, Ken Savage, said that last week's ruling by an appeals court allowing the state to continue sanctioning mask-requiring districts, led him to reverse course.

"Last Friday, the 1st District Court of Appeal instituted a stay, which means the Florida Department of Education can continue to enforce its interpretation of the parental opt out until this matter is ultimately resolved. Therefore, starting on Tuesday, September 14, the School District of Lee County will require face coverings, while allowing parents to opt-out without a medical exemption," Savage said in statement.

Lee County was one of at least 13 districts in Florida defying Gov. Ron DeSantis and requiring masks for students unless they provided a doctor's note exempting them from wearing one.

Savage implemented a mandate on Sept. 1, effective for 30 days, while the district tracked coronavirus-related numbers.

-ABC News' Will McDuffie

Florida Gov. Ron DeSantis is threatening to sue cities in the state that have issued vaccine mandates, for up to $5,000 per infraction.

The governor, who early Monday repeated falsehoods about the COVID-19 vaccines, said hours later, at a press conference, that he's willing to sue the cities because he does not want vaccine mandates to threaten Floridians' jobs.

"We are not gonna let people be fired because of a vaccine mandate," he said.

Meanwhile, over 11,215 patients remain hospitalized in Florida with COVID-19, according to the Florida Hospital Association.

As of Monday, 75% of the state's eligible population has had one vaccine dose, according to the U.S. Centers for Disease Control and Prevention.

-ABC News' Matthew Vann