In South Africa, the National Institute for Communicable Diseases reported 8,561 new COVID-19 cases on Wednesday -- which is nearly double the 4,373 new cases reported on Tuesday.

Seventy-two percent of the new cases were diagnosed in Gauteng province. South African President Cyril Ramaphosa said Sunday that the omicron variant was responsible for most of the infections found in Gauteng over the last two weeks and that the variant is now showing up in all other provinces.

-ABC News' Christine Theodorou

Forecast models used by the CDC -- the COVID-19 Forecast Hub at UMass Amherst -- predict weekly death totals and hospital admissions to increase over the next four weeks.

The model predicts that more than 15,000 Americans will die over the next two weeks, with a total of nearly 810,000 deaths recorded by Christmas.

-ABC News' Arielle Mitropoulos

South Korea on Wednesday confirmed its first cases of the omicron variant.

The Korea Disease Control and Prevention Agency said the new variant was initially detected among three people -- a couple who arrived from Nigeria on Nov. 24 and their friend who drove them home from the airport. Since then, the variant was found in two other people who also traveled to Nigeria and returned to South Korea on Nov. 23, bringing the total of confirmed cases to five.

Health authorities are conducting genetic sequencing tests on the couple's child and relatives of the friend who drove them home to determine if they were also infected, according to the Korea Disease Control and Prevention Agency.

In an effort to fend off the omicron variant, which was first identified in southern Africa last week, South Korea has banned foreign short-term travelers from eight southern African nations. South Korean citizens arriving from those countries must quarantine for at least 10 days, regardless of their vaccination status.

South Korea's daily tally of newly diagnosed COVID-19 infections exceeded 5,000 on Wednesday for the first time since the start of the pandemic. The surge, which officials attributed to the highly contagious delta variant, has pushed COVID-19 hospitalizations and deaths in the country to record highs.

The Korea Disease Control and Prevention Agency said most of the 5,123 new cases were reported in the capital, Seoul, and its surrounding metropolitan region, where officials said earlier that more than 80% of intensive care units designated for COVID-19 patients were already filled.

-ABC News' Joohee Cho

Nigeria confirmed on Wednesday its first cases of the omicron variant.

The new variant was detected among three people with a recent history of travel to South Africa who tested positive for COVID-19 after arriving in the Nigerian capital, Abuja, according to the Nigeria Center for Disease Control.

"These cases were recent arrivals in the country in the past week," Dr. Ifedayo Adetifa, director-general of the Nigeria Center for Disease Control, said in a statement Wednesday. "Follow up to ensure isolation, linkage to clinical care, contact tracing and other relevant response activities have commenced. Arrangements are also being made to notify the country where travel originated according to the provisions of the International Health Regulations."

Following confirmation of the variant on Nigerian soil, the national travel advisory was revised and now requires all inbound travellers to present proof of pre-booked day 2 and day 7 COVID-19 tests as well as a a negative test result that was taken no more than 48 hours before departure. All outbound passengers, regardless of the requirements of the destination countries, are expected to present evidence of full COVID-19 vaccination or a negative test result done no later than 48 hours before departure.

"The NCDC assumes Omicron is widespread globally given the increasing number of countries reporting this variant," Adetifa said. "Therefore, it is a matter of when, not if, we will identify more cases."

The cases of omicron in Nigeria are also the first to be confirmed in West Africa.

-ABC News' James Bwala

At least 10 people have tested positive for COVID-19 on a Cruise Norwegian ship disembarking in New Orleans this weekend, according to the Louisiana Department of Health.

Those infected include both passengers and crew members, officials said.

The Norwegian Breakaway departed from New Orleans on Nov. 28 and stopped in Belize, Honduras and Mexico on its voyage. There are more than 3,200 individuals on board, the health department said.

The company required on-site testing in addition to proof of vaccination before boarding the vessel, according to the Port of New Orleans.

The health department said the cruise line has been adhering to appropriate quarantine and isolation protocols. In addition, everyone aboard the ship will be tested for COVID prior to disembarking.

Those who test positive for COVID-19 on the ship will either travel by personal vehicle directly to their private residence or self-isolate according to current Centers fo Disease Control and Prevention guidelines in accommodations provided by Norwegian Cruise Lines.

"The health and safety of our guests, crew and the communities we visit is our highest priority, and we will continue to take all appropriate actions to ensure their wellbeing and protect public health," a Norwegian Cruise Lines spokesperson told ABC News.

"We have identified a handful of COVID-19 cases among guests and crew onboard Norwegian Breakaway, which is scheduled to disembark in New Orleans, LA on December 5. All of the identified cases onboard are asymptomatic. In addition to requiring that 100% of guests and crew are fully vaccinated, per the Company's comprehensive health and safety protocols, we have implemented quarantine, isolation and contact tracing procedures for identified cases."

The spokesperson said the company is testing all individuals prior to disembarkation, and providing post-exposure and quarantine public health guidance by the CDC.

"Any guests who have tested positive for COVID-19 will travel by personal vehicle to their personal residence or self-isolate in accommodations provided by the Company according to CDC guidelines," the spokesperson said. "We take this matter extremely seriously and will continue to work closely with the CDC, the office of Governor John Bel Edwards, the Louisiana Department of Health as well as the city and port of New Orleans. At this time, there have been no changes to scheduled future sailings on Norwegian Breakaway. We will provide additional updates to impacted guests as appropriate."