Omicron updates: COVID-19 cases could double in New York City

Over 2 million children ages 5 to 11 are now fully vaccinated, White House COVID-19 data director Cyrus Shahpar said.

These kids are among the over 200 million Americans of all ages who are now fully vaccinated, according to the White House.

Shahpar's tweet added, "Early evidence indicates boosters increase protection against Omicron. Get boosted!"

However, roughly two-thirds of parents of elementary school-aged children are either holding off on getting their younger kids vaccinated or refuse to do so, according to a poll released Thursday by the nonprofit Kaiser Family Foundation.

Parents of teens are more willing to get their kids vaccinated, but only about half of that age group have gotten the shot so far, KFF found.

The new findings come despite increasing evidence that the vaccine is safe and that kids and teens are now helping to drive up case numbers.

CDC director Rochelle Walensky has signed off on the recommendation for Pfizer boosters for 16- and 17-year-olds.

"Although we don’t have all the answers on the Omicron variant, initial data suggests that COVID-19 boosters help broaden and strengthen the protection against Omicron and other variants," Walensky said. "I strongly encourage adolescents ages 16 and 17 to get their booster if they are at least 6 months post their initial Pfizer vaccination series."

The FDA authorized Pfizer's booster for 16 and 17 year olds earlier on Thursday.

Pfizer CEO Albert Bourla called this a "critical milestone."

"While new variants, including Omicron, emerge across the globe, we believe that the best way to minimize the spread of COVID-19 and any future variants is getting all eligible people fully vaccinated with the first two dose series and a booster dose as recommended," he said in a statement.

-ABC News' Cheyenne Haslett, Eric M. Strauss

The U.S. is processing 1 million PCR tests each day, CDC director Dr. Rochelle Walensky told ABC News chief medical correspondent Dr. Jennifer Ashton during an interview Wednesday at the CDC’s Emergency Operation Center.

"That gives us a really good window as to test positivity," Walensky said. "It also gives us the samples we need in order to sequence, because we can't sequence from a rapid test."

"The rapid tests, I think, have another important role, and that is to empower people to help make smart decisions," Walensky said. "Don't do a test that you're not going to do anything with the information. Most people now who do a rapid test are doing so either to protect themselves or somebody who they're about to go see or some family member. And so they are generally motivated, I would say, to do the right thing with the result."

-ABC News' Eric M. Strauss, Sony Salzman

The World Health Organization said Thursday that preliminary data indicates hospitalizations in South Africa remain low, offering "signs of hope," despite the fact that the omicron variant is spreading rapidly and weekly COVID-19 cases on the African continent have surged by 93%.

In the week ending on Dec. 5, southern Africa recorded a 140% hike in COVID-19 cases, the highest of any region on the continent for that period, mainly driven by an uptick in South Africa, according to the WHO. While researchers are still working to determine whether omicron is fueling the surge, the WHO said that emerging data from South Africa indicates the new variant may cause less severe illness. Data on COVID-19 hospitalizations across South Africa between Nov. 14 and Dec. 4 show that intensive care unit occupancy was only 6.3%, which the WHO said is very low compared with the same period when the country was facing the peak linked to the delta variant in July.

Furthermore, data from the same two-week period from one of the South African health districts most impacted by omicron show that out of more than 1,200 hospital admissions related to COVID-19, there were 98 patients receiving supplemental oxygen and only four on ventilators. The WHO cautioned that the data is "very preliminary with a small sample size and most of the people admitted to the health facilities were under the age of 40."

Since omicron was first identified in southern Africa in November, confirmed cases of the variant have been reported in 57 countries around the world. In an effort to prevent the spread of the new variant, more than 70 countries have imposed travel bans that are mainly targeting southern African nations, some of which have yet to report any omicron cases, according to the WHO.

"With Omicron now present in nearly 60 countries globally, travel bans that mainly target African countries are hard to justify," Dr. Matshidiso Moeti, the WHO's regional director for Africa, said in a statement Thursday. "Through the diligent surveillance efforts of African scientists, the new variant of concern was first detected on this continent, but it's unclear if transmission was taking place silently in other regions. We call for science-based public health measures to counter the spread of COVID-19. The travel restrictions come at the height of the end-of-year tourist season, ravaging Africa's economies, with a knock-on impact that is potentially devastating to the health of Africans."