In an interview with ABC News' Linsey Davis, U.S. Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said she hopes unvaccinated Americans are spurred into action following Monday's Food and Drug Administration's approval of the Pfizer COVID-19 vaccine.

Walensky said the FDA is "the gold standard for the safety and effectiveness of these vaccines," and the move  was "powerful signal in the safety and effectiveness."

"We have an extraordinary amount of data, and I'm really pleased that the FDA not just took their time and did the due diligence that needed to be done, but did it quickly and efficiently to bring this to the American people as soon as possible," she said.

Walensky didn't have a timetable for when the Moderna vaccine would get full approval since they haven't submitted its data to the FDA yet.

She did say that the current expectation is that the Pfizer vaccine will be authorized for children ages 5 to 12 by November.

While Walensky said she prefers Americans voluntarily get their shots, she encouraged more vaccine mandates to spur people.

"We've already seen just today many come through so that people will recognize if they were on the fence and they just needed that extra push that these mandates will get them there," she said.

Chicago Mayor Lori Lightfoot announced Monday afternoon that city workers will have to get their COVID-19 vaccines.

Lightfoot said that the city has been working with labor unions over the last several weeks to finalize plans.

"It's for the safety of all involved," she said.

Lightfoot did not immediately reveal a deadline or other details about her order.

All large gatherings in Honolulu will be suspended due to a dramatic uptick in cases, Mayor Rick Blangiardi announced Monday.

Health care workers are "pushed beyond their limits," the mayor said.

The ban begins Aug. 25 and will last for four weeks.

Five states have intensive care units over 90% full: Alabama (100%), Florida (92.82%), Georgia (92.95%), Mississippi (93.81%) and Texas (91.27%), according to federal data.

The South also leads the country with the highest case rates. Louisiana and Mississippi have the highest case rates, followed by Florida, Tennessee, Georgia, Arkansas and South Carolina, according to federal data.

More than 95.6% of counties are either reporting high (89.32%) or substantial (6.24%) community transmission, federal data shows. Just 4.41% of counties are reporting moderate or low transmission.

-ABC News' Arielle Mitropoulos

A Tallahassee judge ruled Friday that Florida school boards can enact student mask mandates, going against Gov. Ron DeSantis, who in July issued an executive order that set off a public feud with school districts.

Judge John C. Cooper found that a blanket ban on face masks in schools "does not meet constitutional muster" and ordered the Florida Department of Education to stop enforcing a state rule that requires districts to allow parents to opt-out of mask mandates.

Cooper, over about two hours, picked apart the state's defense, saying the science presented during the weeklong trial did not support the state's argument against masking children.

Ten Florida school districts have adopted mask mandates for students this month. Two -- Broward and Alachua -- were sanctioned by the Florida commissioner of education, who said he would begin withholding the salaries of board members who voted to require masks.

DeSantis will "immediately appeal" the ruling, the governor's press secretary, Christina Pushaw, said in a statement. "This ruling was made with incoherent justifications, not based in science and facts," Pushaw said.

A spokesman for the Florida Department of Education said, "We are immensely disappointed that the ruling issued today by the Second Judicial Circuit discards the rule of law. This decision conflicts with basic and established rights of parents to make private health care and education decisions for children. ... We are committed to the fundamental rights of parents and will push forward on appeal to ensure that this foundation of democracy is upheld."

-ABC News' Will McDuffie