The vast majority of law enforcement deaths last year -- 301 out of a total 458 deaths -- were due to COVID-19, the second year in a row COVID-19 was the leading cause of line-of-duty deaths, according to a new report from the National Law Enforcement Memorial Fund.

"Law enforcement officers nationwide continue to be exposed to the Covid-19 virus in the course of their daily assignments; therefore, the number of line-of-duty deaths is sadly ever-increasing," the report said.

The vaccination status of the 301 officers who died is not known.

The CDC says it plans to update its mask guidance to “best reflect the multiple options available to people and the different levels of protection they provide.”

The CDC did not say when its guidance will be updated. In the meantime, the CDC said in a statement, “any mask is better than no mask, and we encourage Americans to wear a well-fitting mask to prevent the spread of COVID-19.”

Since the arrival of omicron, health experts have urged Americans to upgrade their cloth masks to an N95 or KN95 because the new variant is so highly transmissible. But these higher-grade masks are costly and hard to find.

Prior to omicron, CDC director Rochelle Walensky resisted suggesting N95 masks for the average American because the CDC didn’t want to discourage people from wearing any mask.

Dawn O’Connell, a top official at the Health and Human Services Department, said Tuesday that the Biden administration plans to increase production of N95s. There are already 737 million N95 masks in the strategic national stockpile available for medical workers.

-ABC News' Anne Flaherty

Forecast models used by the CDC suggests COVID-19-related deaths will significantly increase over the next four weeks.

The model forecasts that 22,000 more Americans could die from COVID-19 in just the next two weeks.

The CDC obtains these 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 -- displayed like a hurricane forecast spaghetti plot -- usually with a wide cone of uncertainty.

-ABC News' Arielle Mitropoulos

British Prime Minister Boris Johnson apologized Wednesday for attending a party during England's strict lockdown in 2020.

It was the first time that Johnson acknowledged he went to a garden party at his official residence and office on London's Downing Street in May 2020. He is facing growing anger and calls for his resignation over claims he and his staff flouted COVID-19 restrictions by holding a "bring your own booze" party. At the time, Johnson's government had imposed restrictions barring people in England from meeting more than one individual outside their household.

During the weekly Prime Minister’s Questions session in the House of Commons in London on Wednesday, Johnson said he had considered the garden party to be a work event to thank his staff for their efforts during the pandemic.

"I want to apologize," Johnson told lawmakers. "With hindsight, I should have sent everyone back inside."

The prime minister urged people to await "the full conclusion" of an investigation by senior civil servant Sue Gray into several alleged parties by government staff. Gray will report her findings by the end of the month.

Opposition Labour Party leader Keir Starmer said Johnson's defense was "the pathetic spectacle of a man who has run out of road" and demanded he "do the decent thing and resign."

The prime minister declined to resign and didn't explicitly admit that he had broken any rules, but said he understood "the rage."

"I know that millions of people across this country have made extraordinary sacrifices over the past 18 months," he added. "I understand the anger, the rage that they feel at the thought that people in Downing Street were not following those rules."

-ABC News' Guy Davies, Ian Pannell and Joseph Simonetti