California health officials and hospital administrators are pleading for residents to stay home during the holidays as a record-shattering surge of covid-19 patients pushes the medical system to the brink, with the state opening field hospitals and issuing pleas for more health-care workers to treat the ill.

With one model suggesting the state’s hospitals may be flooded with tens of thousands more patients by mid-January, California Health and Human Services Secretary Mark Ghaly said officials are updating the state’s guidelines for rationing care in the event the system becomes overwhelmed. The goal, he said, is to “work hard to make sure no one has to put them into place anywhere in California.”

The country’s most populous state has emerged as the new coronavirus epicenter, setting nationwide records for cases. The number of Californians hospitalized jumped 65 percent over a two-week period, to nearly 19,000 on Tuesday, and deaths have been hovering at nearly 250 a day, according to Washington Post tracking.

Administrators at some of California’s largest health-care systems warned Tuesday that Christmas and New Year’s gatherings could worsen the already grim picture. Some of the current surge can be attributed to Thanksgiving celebrations, they said, and they fear that if infections continue to mount, their facilities will become so strained they won’t be able to properly care for everyone.

“What we’re seeing right now is the Thanksgiving Day celebration effect,” said Stephen Parodi, the associate executive director of the Permanente Medical Group. “It is related to the travel, it is related to the gathering. We understand why people have done it, but we are really making a clarion and desperate call to Californians to not repeat what happened during Thanksgiving.”

“Our hospital systems cannot afford to see another increase like we’ve seen after Thanksgiving,” Parodi said.

Dec. 16 was a day of relief at Temple University Hospital in Philadelphia. Health-care workers lined up and some even teared up when they received a vaccine. (The Washington Post)

The SOS from medical centers in California was sounded on the same day that hope emerged the nation may be gaining access to an additional trove of coronavirus vaccines.

The Trump administration and Pfizer are close to a deal for the pharmaceutical giant to provide tens of millions of additional vaccine doses through next spring and summer, according to people familiar with the negotiations. The deal could be announced as soon as Wednesday.

As part of the agreement, Pfizer would get help from the federal government in procuring supplies to make the vaccine, said the individuals, who spoke on the condition of anonymity because they were not authorized to talk publicly about the matter.

The race to provide more vaccines appears ever more urgent in places such as Southern California. Hospitals there have resorted to keeping patients in hallways and converted conference rooms, as capacity in intensive care units across the region plummeted in recent days. Some facilities are now operating additional pop-up intensive care units to meet the demand.

But it’s not capacity that medical leaders worry most about. It’s staffing. Doctors, nurses and respiratory therapists are exhausted. At some Kaiser Permanente locations, nurses who usually care for one patient are being asked to handle three, said the system’s CEO, Greg A. Adams.

And it's only going to get worse.

“The crux of the matter is the exhausted workers on the front lines,” said Thomas G. McGinn, an executive vice president at CommonSpirit Health, one of the largest health systems in the nation.

McGinn was in New York during its dire spring surge, and he said what’s happening in California today is “a very similar situation to what I saw in New York.”

Some hospitals have begun postponing elective surgery and the state is implementing a plan to set up “alternate care sites” — better known as field hospitals — that will divert patients struggling with other maladies away from facilities overwhelmed with coronavirus patients.

Vanessa Walker, a medical director at Sutter Health in Northern California, said the surge is evident not only at big urban hospitals such as those in Los Angeles. It’s affecting rural facilities, too. Hospitals that in the past could have transferred patients to larger facilities for specialized care must now handle those patients themselves, she said.

“It’s affecting us all, everywhere,” Walker said.

Kaiser Permanente has not had to implement the state’s crisis standards of care, Parodi said in a statement to The Post. But he said that if the rate of new infections doesn’t slow, “it’s only a matter of time.”

“We hope not to get to the place where we have to start making extraordinarily difficult decisions that most of us have never had to face before,” Parodi said. “But with resources spread so thin — especially staffing — the only way we can avoid reaching crisis levels is if everybody takes action to stop the current spread of the virus.”

The news out of California came as much of the world’s attention remained focused on a new variant of the virus that has proliferated in Britain. There’s no evidence that the variant, officially known as B.1.1.7, causes more severe illness or greater risk of death. But it appears to be more contagious, a revelation that spurred a whirlwind of travel restrictions.

More than 50 countries banned arrivals from the United Kingdom, despite some experts’ belief the new variant may not have originated there. Among them was France, which halted transit along a key European trade route in a particularly disruptive move. On Tuesday, a limited reopening was announced, but France and Britain continued to argue over how to unblock the ports late into the night.

Prime Minister Boris Johnson, who initially said canceling Christmas gatherings would be “inhumane,” is now advising increasingly isolated Britons to do exactly that. More than a quarter of residents are living under strict lockdown, with shops, pubs and restaurants closed.

The U.S. has not imposed restrictions on travel from the United Kingdom, though officials said health authorities have been considering the best course. The Centers for Disease Control and Prevention said Tuesday that B.1.1.7 may already be circulating in the country.

“Ongoing travel between the United Kingdom and the United States, as well as the high prevalence of this variant among current UK infections, increase the likelihood of importation,” the CDC said in a scientific brief. “Given the small fraction of US infections that have been sequenced, the variant could already be in the United States without having been detected.”

There has been no evidence of the new variant in California, where samples are regularly tested. With the state already under enormous strain, Ghaly said health officials would be watching closely, concerned about how it could impact current efforts to contain and mitigate the virus.

“The last thing we want to do,” he said, “is let a new strain of covid come and spread more rapidly or easily across the state.”

Top U.S. disease trackers and drugmakers have said they believe that recently authorized vaccines will be effective against the coronavirus variant identified in the United Kingdom.

The first of those vaccines was produced by Pfizer, in collaboration with the German company BioNTech.

The U.S. government has been seeking an agreement that would provide an additional 100 million vaccine doses of that vaccine for the second quarter of next year. Pfizer has indicated it could provide 70 million in the second quarter and another 30 million in the third quarter, but also that it might be able to get to 100 million doses more quickly if it gets additional manufacturing capability.

The New York Times first reported Tuesday that Pfizer and the administration were close to a deal.

Under an existing contract, Pfizer has committed to providing the government with 100 million doses by the end of March. Moderna, the maker of the second vaccine to be authorized by federal regulators, has agreed to provide the same amount by the end of the first quarter.

Pfizer as recently as October had been urging the government to lock down an additional 100 million doses of its vaccine. But that did not happen, and when administration officials recently said they wanted to buy another 100 million, Pfizer said it had already committed most of its supply to other countries.

One person familiar with the negotiations said a priority for Pfizer has been activation of the Defense Production Act to create better access to some of the ingredients needed to produce the vaccine. The drugmaker has been stressing this point for several months, the person said, because some of the materials it needed had been snapped up by companies given priority under Operation Warp Speed, the government’s vaccine initiative. Michael Pratt, a spokesman for Operation Warp Speed, declined to comment.

Pfizer was the only company that did not take government money for research and development of a vaccine, which meant U.S. officials have had less insight into aspects of its manufacturing process, federal officials have said, and less certainty about where the company’s doses would be sold.

It was expected, the person said, that Wednesday’s deal would resolve this sticking point.

William Booth, Jacqueline Dupree, Derek Hawkins and Rick Noack contributed to this report.