COVID-19 updates: 2 cases of omicron variant confirmed in Canada, officials say

Chief medical adviser to the president, Dr. Anthony Fauci, said he "wouldn't be surprised" if the new COVID-19 variant omicron was already in the United States, on NBC Saturday morning.

"You know, I would not be surprised if it is. We have not detected it yet, but when you have a virus that is showing this degree of transmissibility and you're already having travel-related cases that they've noted in Israel and Belgium and other places, when you have a virus like this, it almost invariably is ultimately going to go, essentially all over," Fauci said.

"Its ability to infect people who have recovered from infection and even people who have been vaccinated makes us say this is something you have to pay really close attention to and be prepared for something that's serious. It may not turn out that way, but you really want to be ahead of it," Fauci also said.

-ABC News' Ahmad Hemingway

Sixty-one people who traveled from South Africa to the Netherlands have tested positive for COVID-19 and will be tested for the newly discovered COVID variant omicron, The Associated Press reported.

Two flights from Johannesburg and Cape Town arrived in the Netherlands Friday, just after the Dutch government, along with other countries, imposed a ban on southern African nations with the discovery of omicron, according to the AP.

Those who tested positive must remain in quarantine for seven days if they have symptoms and five days if they do not.

-ABC News' Ahmad Hemingway

The Centers for Disease Control and Prevention said in a statement Friday that it is "following the details of this new variant," omicron, first reported to the World Health Organization by South Africa.

"We are grateful to the South African government and its scientists who have openly communicated with the global scientific community and continue to share information about this variant with the U.S. Department of Health and Human Services and CDC," the CDC said, adding that it is continuing to learn more about the variant and monitor its path.

No cases of omicron have been identified in the U.S. to date, but on Friday the WHO classified the new variant as a "variant of concern.”

"CDC is continuously monitoring variants and the U.S. variant surveillance system has reliably detected new variants in this country," the CDC said. "We expect Omicron to be identified quickly, if it emerges in the U.S."

The CDC recommends that people traveling to the U.S. continue to follow its guidance for traveling.

Moderna on Friday announced that it is testing three existing COVID-19 vaccine booster candidates to address the newly named omicron variant.

Data on the ability of the current vaccine dose to neutralize the new variant should be available in the coming weeks, the company said in a statement.

Moderna also said the company has been testing variant-specific boosters and is “working rapidly” to advance an omicron-specific booster candidate.

“The mutations in the omicron variant are concerning, and for several days, we have been moving as fast as possible to execute our strategy to address this variant,” Chief Executive Officer Stéphane Bancel said.