Omicron updates: COVID outbreak reported on cruise ship docking in New Orleans

New York City officials reinstated a mask advisory on Monday, “strongly recommending” all residents, regardless of vaccination status, wear masks inside public settings.

Public settings include grocery stores, building lobbies and offices, said Dr. Dave Chokshi, commissioner of the city's Department of Health and Mental Hygiene.

"Masks are still required for everyone in public transit, health care settings, schools and congregate settings," he added.

The omicron variant will likely be detected in New York City in the coming days, Chokshi said.

Health officials are "very, very carefully" monitoring the variant, said Mayor Bill de Blasio.

-ABC News' Aaron Katersky, Brian Hartman, Arielle Mitropoulos

The White House’s Office of Management and Budget is telling federal agencies they should hold off on suspending or firing federal workers for not complying with the vaccine mandate until after the holidays, according to a memo obtained by ABC News. 

This change, which has not yet been publicly announced, comes as President Joe Biden is putting pressure on private employers to embrace their own vaccine mandates. 

Ninety-two percent of federal workers have already had at least one vaccine dose, according to the Office of Management and Budget. The federal workforce's compliance rate stands at 96.5%, meaning employees have had at least one vaccine dose or have a pending or approved exception or extension request.

-ABC News' Anne Flaherty

Dr. Ashish Jha, dean of Brown University's School of Public Health, told NBC's "Today" on Monday that he assumes omicron is already in the United States and predicts the new variant be identified in the next few days.

But Jha said he believes it's "extremely unlikely" that omicron would completely evade vaccines.

"I think that our vaccines will hold up -- the question is … is it a little bit less effective? A lot less effective? We will have that data -- both laboratory data and clinical data -- in the next week or two at the most," Jha said.

"I wouldn't make any major changes to plans" for the holidays yet, he continued. "I would just wait and make sure you're vaccinated and everybody around you is vaccinated."

"If you're fully vaccinated -- and especially if you're boosted -- you're going to have more protection against this variant," he said.

-ABC News' Cheyenne Haslett

Portuguese health authorities on Monday confirmed 13 cases of the omicron variant among professional soccer players.

The Ricardo Jorge National Health Institute said the players who tested positive are all members of the Lisbon-based Belenenses SAD soccer club and that one of them had recently traveled to southern Africa, where the omicron variant was first identified last week.

The institute is investigating whether this is one of the first reported instances of local transmission of the new coronavirus variant outside of southern Africa, where most of the cases have been recorded so far.

All 13 players have been placed in quarantine and those who have been in contact with them were ordered to isolate, regardless of their vaccination status or their exposure to possible contagion. The players and their close contacts will be regularly tested for COVID-19, the institute said.

-ABC News' Aicha El Hammar Castano