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

Maine Gov. Janet Mills said Wednesday that she's activated up to 75 National Guard members to help hospitals overwhelmed with COVID-19 patients.

Maine currently has a record high of 379 COVID-19 patients in hospitals, including 60 people on ventilators, Mills' office said. "The vast majority" of the patients aren't fully vaccinated, the governor's office said.

Only 42 ICU beds are available in the state, according to the governor's office.

Besides the National Guard members, Mills said she's requested federal COVID-19 surge response teams for two hospitals. If approved, the federal government could provide extra doctors, nurses and other staff.

Eleven staff members at Oakland Medical Center in California have tested positive for COVID-19, and most cases are omicron, Kaiser Permanente said in a statement.

Their exposure was linked to an out-of-state wedding, Kaiser Permanente said.

The staffers are isolated at home with mild symptoms, Kaiser Permanente said, adding that they're all fully vaccinated, including boosters.

"The potential window of exposure at our facility was brief and isolated, as the few affected staff members, who are in patient-facing roles, worked briefly prior to being symptomatic or tested and all adhered to COVID-19 infection prevention guidance," Kaiser Permanente said. "We have identified 8 patients and 8 staff who were potentially exposed; 13 have tested negative for COVID-19 and the remainder are in process. To date, there have been no COVID-19 cases among them."

A new CDC forecast predicts that the U.S. COVID-19 death toll could reach between 821,000 and 837,000 by Jan. 1, 2022.

The U.S. death toll currently stands at 792,883.

The CDC obtains its forecasts from the COVID-19 Forecast Hub at UMass Amherst, where a team monitors and combines forecasting models from the nation’s top researchers. The team then creates an ensemble forecast, usually with a wide cone of uncertainty.

-ABC News' Arielle Mitropoulos

England will move to "plan B" ahead of Christmas, with the government advising people to work from home if they can beginning on Monday, Prime Minister Boris Johnson said during a press conference Wednesday at 10 Downing Street.

Johnson warned, "It's become increasingly clear that omicron is growing much faster than the previous delta variant and is spreading rapidly around the world."

He said there's evidence that omicron cases in the U.K. could double in two or three days.

-ABC News' Ibtissem Guenfoud