Los Angeles County reported 102 new deaths on Thursday, marking the highest daily death toll since March 10, 2021.

Daily deaths doubled in just one week, according to county officials.

Of Thursday's 102 fatalities, 90% were residents who tested positive for COVID-19 after Christmas Eve, which means they likely had omicron, county officials said in a statement.

"As deaths often lag behind surges in cases and hospitalizations, we may see an even higher number of deaths in the coming weeks," county officials warned.

The positivity rate in New York state has dropped to the single digits for the first time since Dec. 20, Gov. Kathy Hochul announced on Friday, another indicator that the omicron surge is receding in the state.

The positivity rate now stands at 9.75%, down from over 23% on Jan. 2, which was the highest rate in New York during the omicron wave. 

"This is still to be taken very seriously," Hochul stressed at a Friday briefing, noting that hospitalizations are still high.

-ABC News' Will McDuffie

The CDC says three new studies show the importance of vaccines and boosters in protecting against severe COVID-19 infection from delta or omicron. 

The first study found that a third shot slashed the risk of an emergency room or urgent care trip by 94% during delta and 82% during omicron. 

The second study found that, during the delta and omicron waves, the unvaccinated were nearly 14-times more likely to be infected and 53-times more likely to die compared to people who are vaccinated and boosted. 

The third analysis found that three doses of a COVID-19 mRNA vaccine -- as opposed to two doses or none -- provided protection against both delta and omicron against symptomatic infection. However, the protection was greater against delta compared to omicron. 

-ABC News' Arielle Mitropoulos

The U.S. is now reporting an average of about 745,000 new cases per day, down by about 5% in the last week, according to federal data. It is still unclear whether the nation is experiencing a true plateau or whether data is skewed from the holiday weekend.

In the last month alone, the U.S. recorded 18.2 million new cases, according to Johns Hopkins University data -- more than one-quarter of the nation's total number of confirmed cases reported since the onset of the pandemic.

There's growing evidence to suggest the latest omicron surge continues to recede in the parts of the country first struck by the variant.

In New York, daily cases have dropped by nearly 38% in the last week, and in New Jersey, new cases are down by 45.8%, according to federal data.

-ABC News' Arielle Mitropoulos