In Wisconsin, only 4% of ICU beds are available.

"This is getting really scary," Dr. Jamie Hess, an emergency physician at the University of Wisconsin, told ABC News.

"We're really reaching a crisis point where we have more patients to take care of then we have beds in the hospital or staff to care for them," Hess said.

Michigan has been struggling through a similar surge for nearly three months, with the state reporting more than 6,500 new cases each day. On average, more than 500 patients are being admitted to hospitals each day.

"Where we are right now feels a lot like the first surge back in March of 2020," Erin Dicks, a nurse manager at MICU Henry Ford Hospital, told ABC News. "We don't have enough beds to be able to manage this."

Dicks said so many patients are young.

"I think one of the biggest frustrating pieces for my staff is that they look at this as, this is preventable -- people don't have to die here," Dicks said.

-ABC News' Arielle Mitropoulos

Harvard University will require boosters for all eligible members of the community, school officials said Thursday.

Earlier this week, Harvard warned of an increase in cases, saying the rise can be attributed to social events following the Thanksgiving break.

Omicron is likely already on campus, university officials added.

Harvard joins a growing list of colleges and universities moving to require third doses next semester for those eligible. Other schools include Stanford, NYU, University of Notre Dame, Syracuse, Smith College and Wellesley College.

-ABC News' Arielle Mitropoulos

In Illinois, 11,858 new cases were reported on Thursday -- the highest daily case number of all of 2021, ABC Chicago station WLS reported, citing state health officials.

Illinois confirmed its second omicron case Wednesday, detected in a suburban Chicago resident. That person is asymptomatic and vaccinated, WLS reported.

The Centers for Disease Control and Prevention has signed off on its advisory committee's recommendation that people who have a choice should get an mRNA vaccine, either Pfizer or Moderna, over the single-shot Johnson & Johnson vaccine.

The updated recommendation comes after a review of new CDC data on rare blood clots linked to the J&J vaccine.

"Today's updated recommendation emphasizes CDC's commitment to provide real-time scientific information to the American public," CDC Director Dr. Rochelle Walensky said in a statement. "I continue to encourage all Americans to get vaccinated and boosted."

A journalist traveling alongside U.S. Secretary of State Antony Blinken on his visit to Southeast Asia has tested positive for COVID-19 in Malaysia, according to U.S. Department of State spokesperson Ned Price.

Meanwhile, Blinken and his senior staff all tested negative for COVID-19 upon arrival in Kuala Lumpur on Tuesday night. The member of the traveling press pool who tested positive had last tested negative in Indonesia's capital, their previous stop, on Tuesday.

"The individual who tested positive will remain in isolation," Price said in a statement Wednesday, "and we will continue to adhere to and go beyond CDC guidance, including with our rigorous testing protocol, for the remaining traveling party."

Blinken has canceled a scheduled trip to Thailand "out of an abundance of caution" and will return home to the United States, according to Price.

"The Secretary expressed his deep regret to the Foreign Minister that he would not be able to visit Bangkok this week," Price said. "He explained that, in order to mitigate the risk of the spread of COVID-19 and to prioritize the health and safety of the U.S. traveling party and those they would otherwise come into contact with, the Secretary would be returning to Washington, D.C. out of an abundance of caution."

"The Secretary extended an invitation for the Foreign Minister to visit Washington, D.C. at the earliest opportunity and noted that he looked forward to traveling to Thailand as soon as possible," Price added. "They affirmed that they would use the upcoming engagements to further deepen the U.S.-Thai alliance."

The U.S. Embassy in Malaysia confirmed that the infected individual "was not involved and has not participated in any of Secretary Blinken's program in Kuala Lumpur."

"The sole member of the traveling party who tested positive is observing all requirements of the Ministry of Health," the embassy said in a statement Wednesday. "We confirm all other members of the party tested negative for COVID-19 upon arrival in Malaysia."

Blinken was in Indonesia on Tuesday, and the U.S. Embassy in Jakarta confirmed that no members of the traveling party tested positive for COVID-19.

All members of the U.S. delegation are required to be vaccinated against COVID-19 and undergo regular testing on trips.

-ABC News' Conor Finnegan