WHO sounds warning over fast-spreading Omicron

The fast-spreading Omicron variant is now the dominant strain of Covid-19 in the United States, health authorities reported Monday, as the WHO called for greater efforts to ensure the pandemic ends next year.

The new variant has helped fuel record case surges, forcing a return to harsh restrictions in some countries. But in the United States, President Joe Biden does not plan on "locking the country down," press secretary Jen Psaki said earlier in the day.

Omicron now accounts for 73.2 percent of new US cases over the past week ending Saturday, the Centers for Disease Control and Prevention said. In some regions of the country -- the Pacific Northwest, South and parts of the Midwest -- it already comprises more than 90 percent of new infections.

With Biden set to deliver an address on Covid-19 Tuesday, the White House reported that a mid-level, fully vaccinated and boosted staff member had tested positive for Covid-19 after spending 30 minutes in proximity to the president three days prior. Biden has so far tested negative.

Early data suggests Omicron could be more infectious and possibly have higher resistance to vaccines, despite indications that it is not more severe than the Delta variant.

Since it was first reported in South Africa in November, Omicron has been identified in dozens of countries, dashing hopes that the worst of the pandemic is over.

WHO director general Tedros Adhanom Ghebreyesus called for nations to redouble efforts to help end the pandemic, calling for new year events to be canceled because it was better to "celebrate later than to celebrate now and grieve later. "We have to focus now on ending this pandemic," he said.