With the coronavirus surge driving thousands of new infections daily, New Jersey hospitals have barred most visitors; federal strike teams were assigned to York and Scranton hospitals; and workers, companies, and unions were adjusting to the CDC’s shortened isolation guidelines.

New Jersey is now averaging more than 15,000 new coronavirus cases a day, a steep increase since two weeks ago, when the seven-day moving average was just under 4,500 cases a day.

Case numbers also continue rising in Pennsylvania, which was averaging 10,770 new coronavirus cases a day over the last week as of Wednesday, according to data from the Department of Health and Human Services and the New York Times. Case rates in Philadelphia hit an all-time high this week.

» READ MORE: As virus cases soar, some districts consider remote learning. Philly keeps its plan to reopen schools next week.

Nationwide, the number of new infections is skyrocketing as the delta and omicron variants combine with holiday gatherings and travel. Just after Christmas and before New Year’s Eve, the United States is recording more than 260,000 new cases a day. That rate is the country’s highest ever, just surpassing the average from January 2021, according to the Times data.

Meanwhile, debate continued over the new CDC guidance allowing people who test positive to isolate for five days rather than 10. Officials made the recommendation to help avoid worker shortages in essential industries, such as air travel and emergency response, the Washington Post reported Wednesday, concerned that keeping people with mild or no symptoms in isolation for 10 days would become too disruptive to society.

Some experts have questioned that motivation, saying the CDC should have recommended a negative antigen test after five days. And some workers’ unions said they had concerns about employees potentially spreading the virus or working while sick, while many employers applauded the move.

Ashish Jha, dean of Brown University’s public health school, said on Twitter that the CDC’s guidance was a “step in the right direction” but should have included an antigen test requirement for ending isolation.

» READ MORE: Worries that the omicron surge could lead to a breakdown in essential services spurred the CDC’s new isolation rules

Shortening the isolation period for people who are asymptomatic “seems reasonable,” said Darren Mareiniss, an emergency medicine doctor at Einstein Medical Center. But for people who have symptoms, the CDC’s vague recommendation that they isolate until their symptoms “begin to resolve” requires them to judge when they aren’t infectious. That can be tricky, especially when symptoms like fevers can be intermittent.

”It puts a lot of onus on the patient or employees to make these decisions about when they can leave isolation,” said Mareiniss. He continues to advise patients who are symptomatic to stay home for 10 days or until their symptoms go away and they do not have a fever.

“In a perfect world, it would be better not to have people return so quickly,” he said. But, “we have a tremendous shortage of health-care workers and a lot of our workers are becoming ill. There’s some sense this could help get people out of isolation.”

Because federal guidance has frequently shifted as the science around the coronavirus has evolved, some nurses were concerned, too, that the change in guidelines made it hard to know the best course of action.

Shifts like this one can be unsettling for health-care workers caring for patients sick with the virus: “It’s hard to direct health-care workers,” said Maureen May, a nurse at Temple University Hospital and president of the Pennsylvania Association of Staff Nurses and Allied Professionals.

But, she added, “if we’re working in the best interest of public health, we’re OK with the changes.”

» READ MORE: Philly is averaging record-high COVID-19 cases, but officials hope this wave will have fewer hospitalizations

Some leaders of the region’s largest police departments said the surge hasn’t yet had an effect on their operations and noted they’re accustomed to dealing with the virus and its accompanying precautions.

“Law enforcement is certainly an industry that can’t work remotely,” said Bensalem Public Safety Director Fred Harran. “We have to be in and working the streets. We did that back in 2020, and we’ll continue. We’re used to it now.”

John McNesby — president of the Fraternal Order of Police Lodge 5, the union for city police officers — echoed that sentiment, saying the level of concern among officers seemed to be lower during this surge and, as far as he knew, had not caused major staffing issues.

“We’re still out there doing the job,” McNesby said.

With the strain on hospitals mounting in New Jersey, health systems throughout the state banned visitors, except for certain patients, such as children, people in labor, or those with cognitive impairments, the New Jersey Hospital Association reported Wednesday.

“We are sympathetic to patients and their loved ones that want to visit in the hospital,” the association said in a statement. “These guidelines aim to balance that with our overarching priority — and that is to protect our patients, visitors and healthcare workers from COVID transmission.”

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The White House said the federal government would open free coronavirus testing sites in New Jersey and Philadelphia in January, part of a larger deployment of resources nationwide.

In Pennsylvania, the federal government will also send strike teams to hospitals based in York and Scranton to open more acute-care beds, the Pennsylvania Department of Health announced Wednesday. High hospitalization numbers in northern, central, and western parts of the state led Gov. Tom Wolf this month to request the aid from the Federal Emergency Management Agency.

The hospital and EMS workers will be deployed around Jan. 3 for 30 days; the number who will come has not been determined.

While the teams will help, residents need to try to prevent catching or spreading COVID-19 to decrease the number of people needing emergency-room care, said Pennsylvania acting Health Secretary Keara Klinepeter, who was appointed earlier this month to replace Alison Beam.

“By getting vaccinated against COVID-19, individuals are far less likely to be hospitalized after testing positive,” Klinepeter said. “We need all Pennsylvanians to do their part to support their local hospital and get through these winter months.”

Staff writers Vinny Vella, Rob Tornoe, and Chris Palmer contributed to this article.