WASHINGTON - US health experts on Thursday urged Americans to prepare for severe disruptions in coming weeks as the rising wave of COVID-19 cases led by the Omicron variant threatened hospitals, schools and other sectors impacting their daily lives.

The warning came amid record US COVID-19 cases, while federal officials issued more travel warnings and reportedly prepared to authorize booster shots for 12 to 15-year-olds next week.

For the second day in a row, the United States had a record number of new cases based on the seven-day average, with more than 290,000 new infections reported each day, a Reuters tally showed.

At least 18 states and Puerto Rico have set pandemic records for new cases, according to the tally. Maryland, Ohio and Washington, DC, also saw record hospitalizations as overall US COVID-19 hospitalizations rose 27%. 

The surge comes amid increased holiday travel, with New Year's celebrations still to come, and as schools grapple with students' return to classrooms following winter breaks.

"We are going to see the number of cases in this country rise so dramatically, we are going to have a hard time keeping everyday life operating," Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, told MSNBC.

"The next month is going to be a viral blizzard," he said. "All of society is going to be pressured by this."

Dr. Anthony Fauci, the nation's top infectious disease official, on Wednesday said cases will likely rise throughout January.

He and other US health officials have said early data show Omicron appears less severe but have continued to push vaccinations, masks and physical distancing. The Centers for Disease Control and Prevention (CDC) has also issued new guidelines shortening isolation and quarantine periods, which have been criticized by some disease experts.

The New York Times reported on Thursday that US health regulators planned to approve a third vaccine dose for 12 to 15-year-olds next week. Boosters are already approved for those 16 and older.

With testing shortages and breakthrough cases, experts warn the surge will still upend hospitals, emergency response services, schools and retailers, among others, in coming weeks.

"We have to be really careful about being too dismissive of Omicron," Dr. Peter Hotez, an infectious disease expert at Baylor College of Medicine, told CNN.

Rising hospitalizations as healthcare workers are sidelined with their own COVID-19 infections is also concerning, as are fewer effective therapeutics, Hotez said. "We're in for a pretty serious time."

Already, 825,663 people have died in the United States from COVID-19 since early 2020, data showed, with the latest wave of hospitalizations driven by those not vaccinated.

President Joe Biden this month announced new plans to combat Omicron, including federal reinforcements for hospitals and more tests. But some experts have said it is too little, too late.

'BETTER TOOLS'

So far, however, the economy appears steady even as some economists express caution.

While airline travel has been widely disrupted and some hard-hit areas have seen shuttered businesses and canceled events, other measures of activity - such as holiday sales - have held up.

The labor market also is holding its ground. New claims for state unemployment benefits fell last week to their lowest level of the pandemic, the Labor Department said on Thursday.

Cruise operators took a hit on Thursday, however, after the CDC warned people to avoid cruises regardless of their vaccination status amid a growing number of outbreaks onboard.

Still, Jason Greenberg, head of economics at Homebase, which tracks data for about 50,000 small businesses, told Reuters he expects the first week of January to be slower than projected before Omicron but that the rest of the month "will likely depend" on what policies states and cities enact and how cases unfold.

How schools handle the surge is also key, especially for working parents, with systems in Washington and New York vowing to stay open with more testing.

"We can't shut down our city again," New York City Mayor-elect Eric Adams said while unveiling his plan on Thursday to fight COVID-19 while keeping the country's most populous city open for business.

US Education Secretary Miguel Cardona acknowledged staffing woes but urged schools to keep kids in classrooms.

Unlike last year's shutdowns, "we have better tools now. They should remain open," he told MSNBC, adding that federal funds remain available to bolster staffing and testing.

Randi Weingarten, head of the American Federation of Teachers union, separately told MSNBC schools should remain open but some localities may not be able to do so and may need remote options.

Meanwhile, some US colleges have delayed their next semesters or shifted online.

Things should thaw after January, as testing shortages ease and recently-approved medicines become more widely available, experts said.

"We do have light at the end of the tunnel," Osterholm said. "But for right now, you're going to have to hunker down."

Reuters