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

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."

The Food and Drug Administration has authorized the first monoclonal antibody therapy for use before COVID-19 exposure. 

AstraZeneca's Evusheld antibody cocktail can now be given to certain people for preventative use against the virus, including those who are moderately to severely immunocomromised due to a medical condition or medication, and those who have a history of severe adverse reactions to a COVID-19 vaccine. People also must not be currently infected with COVID-19 or have been recently exposed to the virus.

In a recent Phase III clinical trial, AstraZeneca found that the therapy reduced the risk of developing symptomatic COVID-19 infections by 83% in people who did not have the virus, had not been exposed to it and were unvaccinated, when compared to the placebo group.

AstraZeneca told ABC News it is testing the product against the new omicron variant and is "hopeful" that it will hold up against it. Results are expected to become available "within weeks," the company said. So far, Evusheld has been found to neutralize all previous COVID-19 variants of concern, it said.

AstraZeneca said it has agreed to supply the U.S. government with 700,000 doses of Evusheld, which will be distributed to states and territories at no cost and on a pro-rata basis.

-ABC News' Sasha Pezenik