COVID updates: Team USA figure skater Vincent Zhou tests positive at Olympics

Despite the emergence of the omicron variant and increased concerns over waning vaccine immunity, new data from the CDC shows that vaccines are still dramatically reducing the risk of testing positive, requiring hospitalization, or dying of COVID-19.

In December, unvaccinated adults had a three times greater risk of testing positive for COVID-19, compared to vaccinated individuals. Previously reported data, published last month, showed that the unvaccinated were 15 times more likely to die from COVID-19 in November.

Similarly, in December, unvaccinated adults were five times more likely to test positive, compared to fully vaccinated and boosted Americans.

Unvaccinated adults, ages 30 to 49 years old, also saw the highest case-incidence rate while omicron was surging.

-ABC News' Arielle Mitropoulos, Cheyenne Haslett

CDC Director Rochelle Walensky has given the greenlight on full approval for Moderna's vaccine for all adults, which was the last step in the process for the vaccine to move from an emergency use authorization to a permanent approval.

Walensky's ruling came after the CDC's advisory committee voted unanimously Friday to give the Moderna vaccine full approval.

It has been nearly a year since Moderna received emergency use authorization.

-ABC News' Arielle Mitropoulos, Cheyenne Haslett

The U.S. has surpassed 900,000 confirmed COVID-19-related deaths, according to data compiled by Johns Hopkins University.

The death toll currently stands at 900,334.

The U.S. has had over 76 million COVID-19 cases since the pandemic began.

-ABC News' Arielle Mitropoulos

In Oklahoma, where just 9% of ICU beds are available statewide, for health care workers "every day is just filled with nonstop suffering," a nurse told ABC News.

"I just pray I don't have to zip up another body bag, I don't have to call someone and let them know that their loved one's not coming home," Kelly Hale, a nurse at Mercy Hospital Oklahoma City, told ABC News. "We're all just one patient away from an emotional breakdown."

"The majority of our patients are unvaccinated which adds just a whole other level of difficulty for us," Hale said.

She continued, "No one really knows how many tears I shed. Not my family, not my friends. I really want them to know."

"Just please be nice if you know someone in the health care field that's going through this," Hale said. "Just reach out see if they're okay."

-ABC News' Arielle Mitropoulos