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

Japan has suspended the use of about 1.63 million doses of Moderna's COVID-19 vaccine due to reported contamination, as the country grapples with surging infections.

Japanese drugmaker Takeda Pharmaceutical Co., which is in charge of distributing the Moderna vaccine in Japan, said in a press release Thursday that it has received reports of foreign substances in some unused vials at multiple inoculation sites. Although some doses might have been administered, Takeda said there have been no reports of safety concerns tied to the affected vials so far.

After consulting with Japan's Ministry of Health, Labor and Wealth, Takeda said it decided as a safety precaution to stop using doses from three separate lots, manufactured in the same production line as the contaminated vials. The company said it has requested Moderna to conduct an emergency investigation into the issue.

For doses from non-suspended lots, Takeda urged people to check the vials for discolouration, foreign substances or other abnormalities before continuing to use. Meanwhile, the Japanese health ministry said it will work with Takeda to supply alternative doses in an effort to minimize the impact on the country's vaccination progress.

Moderna told ABC News that it has put the 1.63 million doses on hold in Japan after being notified that some of the vials may have been contaminated. One of the three lots received "several complaints of particulate matter" in its vials, the American drugmaker said, while the two other adjacent lots were put on hold out of "an abundance of caution" and for continued assurance of quality.

According to Moderna, the manufacturing issue may have come from one of the lines used at its contract manufacturing site in Spain. The Massachusetts-based company said it is looking into the contamination reports and "proactively communicating with Japan’s health authorities and its partners as the investigation proceeds." Moderna added that it remains "committed to working transparently and expeditiously" with its Japanese distribution partner and with regulators to address any potential concerns. No safety or efficacy concerns have been identified so far, the company said.

Moderna noted that the pause in Japan does not impact doses distributed in the United States, or put the American supply at risk in any way.