A drive-through testing site in Oakland, Calif., on Thursday.
Credit…Jim Wilson/The New York Times

When infections began rising sharply in the U.S. in September, the growth was driven largely by outbreaks in the Upper Midwest. States like North Dakota and Wisconsin soon became the hardest hit in the nation, relative to their size, and the region continues to struggle.

Now, though, with the whole country’s daily average of new cases is as high as it has ever been — over 171,000 — the most rapid growth is happening elsewhere. Nine states are reporting more than twice as many new cases a day as they did two weeks ago, and none of them are in the Midwest.

The surges in those states — Arizona, California, Delaware, Louisiana, Maryland, New Hampshire, New Mexico, Pennsylvania and Vermont — reflect a still-escalating national crisis. Officials warn that it will only get worse if people disregard warnings about travel and get-togethers for the approaching holidays.

“Let me be very clear: A Thanksgiving gathering this year may very well lead to a funeral,” said Gov. Michelle Lujan Grisham of New Mexico, whose state is home to five of the 10 metropolitan areas in the country where new case reports are rising the fastest. “The virus is at large,” the governor said. “Know the risks and respect them.”

Forty-five states are seeing sustained increases, and 17 states added more cases in the seven-day period that ended Sunday than in any other week of the pandemic. Major metropolitan areas that are reporting new cases at or near record levels are all across the continent: Pittsburgh. Albuquerque. Baltimore. San Diego.

Some that have been bad for a while, like El Paso, are coping with the flood of hospitalizations that generally follow a couple of weeks behind a rising tide of new cases. A major hospital group in Arizona, Banner Health, began banning most visitors from its facilities Sunday night because of the worsening spread of the virus.

And where the hospitals come under intense strain, officials are turning, however reluctantly, to impose or reimpose restrictions in the hope of flattening the curve. In Los Angeles County, Calif., which has been averaging more than 3,500 cases a day lately, officials said on Sunday that barring indoor restaurant dining was no longer sufficient, and that outdoor dining would have to shut down as well.

“Unfortunately, if our cases and hospitalizations continue to increase, we will need to issue further restrictions to protect our health care system and prevent more deaths,” said Barbara Ferrer, the county public health director.

A volunteer in Oxford, England, last week received the vaccine made by AstraZeneca and the University of Oxford.
Credit…Andrew Testa for The New York Times

The drugmaker AstraZeneca announced on Monday that an early analysis of some of its late-stage clinical trials, conducted in the United Kingdom and Brazil, showed that its coronavirus vaccine was 70.4 percent effective in preventing Covid-19, suggesting that the world could eventually have at least three working vaccines — and more supply — to help curb the pandemic.

The British-Swedish company, which has been developing the vaccine with the University of Oxford, became the third major vaccine developer this month to announce encouraging early results, following Pfizer and Moderna, which both said that their vaccines were about 95 percent effective in late-stage studies.

AstraZeneca’s results are a reassuring sign of the safety of the vaccine. It came under global scrutiny after AstraZeneca temporarily paused its trials in September to investigate potential safety issues after a participant in Britain developed a neurological illness.

Oxford and AstraZeneca said they would submit their data to regulators in Britain, Europe and Brazil and seek emergency authorization.

The company said its early analysis was based on 131 coronavirus cases. The trials used two different dosing regimens, one of which was 90 percent effective in preventing Covid-19 and the other of which was 62 percent effective.

The regimen that was 90 percent effective involved using a halved first dose and a standard second dose. Oxford and AstraZeneca also said that there were no hospitalized or severe cases of the coronavirus in anyone who received the vaccine, and that they had seen a reduction in asymptomatic infections, suggesting that the vaccine could reduce transmission.

AstraZeneca’s vaccine is expected to come with relatively simple storage requirements, which would be an asset once it gets rolled out. The company has said it anticipates the vaccine will require refrigeration, though it has not provided details about how long and at what temperature it can be kept. Moderna’s vaccine can be kept for up to a month at the temperature of an ordinary refrigerator. Pfizer’s can be kept for up to 5 days in conventional refrigerators, or in special coolers for up to 15 days, but otherwise needs ultracold storage.

AstraZeneca has said it aims to bring data from its studies of its vaccine being conducted overseas to the Food and Drug Administration — which would mean that the agency will likely review and authorize a vaccine before late-stage data are ready on how well the vaccine works in American participants. British regulators already have been conducting a so-called rolling review of the vaccine.

“Today marks an important milestone in our fight against the pandemic,” AstraZeneca’s chief executive, Pascal Soriot, said. “This vaccine’s efficacy and safety confirm that it will be highly effective against Covid-19 and will have an immediate impact on this public health emergency.”

Professor Andrew Pollard, the chief investigator of the Oxford Vaccine Trial, said that “these findings show that we have an effective vaccine that will save many lives.”

AstraZeneca’s results could significantly strengthen the global effort to produce enough vaccine to create population immunity: The price of the shot, at $3 to $4, is a fraction of that of some other potential vaccines, and AstraZeneca has pledged to make it available at cost around the world until at least July 2021 and in poorer countries in perpetuity.

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Gov. Andrew M. Cuomo of New York announced new restrictions in parts of the state where coronavirus cases are rising as Thanksgiving approaches, and warned that the state is on track for a further resurgence of the virus.CreditCredit…James Estrin/The New York Times

As Thanksgiving approaches, Gov. Andrew M. Cuomo of New York on Monday announced new restrictions in parts of the state where virus cases are rising, including New York City, and issued a grim warning that the state was on track for a further resurgence of the virus.

The new restrictions included a zone in Upper Manhattan, the first time the state has rolled back reopening in the borough under its program of targeting so-called microclusters.

“These are dangerous times that we’re in,” Mr. Cuomo said at a news conference in New York City.

Over the last three weeks, the number of people hospitalized with the virus in the state has more than doubled, to 2,724 on Monday from 1,227 on Nov. 2. The number is a far cry from the peak of the pandemic in the spring, when more than 18,000 people were hospitalized.

But Mr. Cuomo warned that if current patterns held, the state would hit 6,000 hospitalizations in another three weeks. The increase could become steeper, he said, if people continued gathering for Thanksgiving and Christmas in the coming weeks, which he called “37 days of the highest socialization of the year.”

The governor again warned residents not to travel for the holidays. The state has currently imposed a 10-person limit on private gatherings in hopes of limiting small parties that he has said have contributed to the resurgence of the virus in the state this fall.

Parts of Upper Manhattan, including Washington Heights, will now be a yellow zone under the state’s tiered, color-coded restriction system. Gatherings will be limited to 25 people, with houses of worship limited to 50 percent capacity. Restaurants can serve only up to 4 people at a table.

Mr. Cuomo also announced an orange zone, the second level of limits, in southern parts of Staten Island. In those areas, indoor dining will close, as will some nonessential businesses deemed to be high risk, such as gyms and personal-care services. All gatherings will be limited to 10 people, with houses of worship limited to 33 percent capacity and 25 people maximum. Other parts of the borough will become a yellow zone.

“Staten Island is a problem,” Mr. Cuomo said.

The borough has been a hot spot for the virus in the city in recent months. Mr. Cuomo said that hospitalizations there had increased enough that Staten Island was facing a capacity issue. As a result, the state will open an emergency coronavirus patient facility in the South Beach neighborhood, a move reminiscent of field hospitals set up in the spring, when New York City was one of the hardest hit places in the country.

The state also announced new yellow zones in parts of Long Island, including Great Neck, Riverhead and Hampton Bays, and expanded yellow and orange zones upstate, around the cities of Rochester and Syracuse.

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The British Prime Minister Boris Johnson announced on Monday that England would return to a tiered system of coronavirus restrictions, and would reopen gyms, stores, and hair salons across the country after the lockdown ends.CreditCredit…Tolga Akmen/Agence France-Presse — Getty Images

Gyms, stores and hair salons will be allowed to reopen in England next week, Prime Minister Boris Johnson said Monday, telling lawmakers that for the first time since the spread of the coronavirus the country could “see a route out of the pandemic.”

Speaking to Parliament by video link, Mr. Johnson said that he would lift a national lockdown on Dec. 2, as expected, and that England would then return to a regionalized system of restrictions based on three tiers of controls.

However, the new plan will keep substantial restrictions on pubs and restaurants — a move that risks friction with some of Mr. Johnson’s own lawmakers, who fear that the hospitality trade will be hit hard by the limitations.

Crucially, the government has not yet announced which parts of the country will be subjected to which set of restrictions, though that information is expected later this week.

Mr. Johnson, who has been quarantining since last week after being exposed to a member of Parliament who tested positive, hailed the progress announced by the team at Oxford University developing a vaccine with the British-Swedish drugmaker AstraZeneca, adding that the “scientific cavalry is in sight.”

There have been at least 1.5 million confirmed cases of coronavirus in the United Kingdom, according to Public Health England. As of Monday morning, 55,024 people had died.

Under the plan to ease restrictions, gyms, stores and hair salons will reopen and collective worship, weddings and outdoor sports will be allowed to resume in all parts of England.

But in the worst-affected parts of the country, pubs and restaurants will stay closed except for takeout service.

In some other areas, people will only be able to drink in pubs if they are also eating a meal. Those pubs will, however, be allowed to stay open until 11 p.m., an hour later than had been allowed immediately before the lockdown began, though the bars will have to take last orders for alcohol at 10 p.m.

Some spectators will be allowed into sports events, though even in the least-affected parts of England, crowds will be limited to a maximum of 4,000, and in some parts of the country none will be allowed.

The package outlined by Mr. Johnson reflected his desire to prevent another surge in virus cases while seeking not to antagonize his backbench lawmakers, who have threatened to rebel over lockdown measures.

Dr. Haleh Farzanmehr administered a coronavirus test to Gov. Gavin Newsom of California last month at a testing facility in Valencia, Calif.
Credit…Pool photo by Marcio Jose Sanchez

Gov. Gavin Newsom of California has gone into quarantine, along with his family, after three of the governor’s children were exposed to a state highway patrol officer who later tested positive for the coronavirus.

The governor’s whole family — Mr. Newsom; his partner, Jennifer Siebel Newsom; and their four children — tested negative for the virus on Sunday, but will stay apart from other people for two weeks anyway, in compliance with state guidelines, his office said.

“We are grateful for all the officers that keep our family safe and for every frontline worker who continues to go to work during this pandemic,” the governor said on Twitter.

The Newsoms learned of the exposure on Friday evening, the governor’s office said. The whole family waited until Sunday to be tested in order to reduce the likelihood of a false negative result (it can take time for the virus to build up to detectable levels after infection). The governor and his partner did not come in direct contact with the officer.

One of the Newsom children was already in quarantine after a classmate tested positive, Politico reported on Friday. The governor has come under fire for sending his children back to their private school classrooms while many public schools in the state remained closed and most families had to adapt to at-home learning.

Mr. Newsom has also faced outrage over his recent decision to attend a birthday dinner at a restaurant in Napa Valley with members of several other households.

With infections and hospitalizations each rising at an alarming rate in the state, officials announced a curfew last week, and some counties and the state have reimposed sweeping restrictions they had been gradually lifting.

According to a New York Times database, the state has reported an average of 11,802 new cases a day over the last week, a sharp increase from a month ago. The figure exceeds the state’s earlier peak of just over 10,000 new cases a day in late July.

The curfew bars nearly all Californians from being away from their homes from 10 p.m. to 5 a.m. except for essential purposes, and is scheduled to last through Dec. 21.

In Los Angeles County, where indoor dining has been shuttered for months and virus cases are still surging, health officials took the additional step on Sunday of closing down outdoor dining “to reduce the possibility for crowding and the potential for exposure.” That order takes effect on Wednesday, just before Thanksgiving.

The Advisory Committee on Immunization Practices of the C.D.C. indicated in a meeting on Monday that health care workers should be the first recipients of coronavirus vaccines.
Credit…Go Nakamura/Getty Images

An expert committee charged with deciding which Americans should be first in line for a coronavirus vaccine met on Monday afternoon to discuss a number of questions before it votes — likely by mid-December — on final recommendations for the Centers for Disease Control and Prevention.

After the group, the Advisory Committee on Immunization Practices, delivers its recommendations, the C.D.C. director, Dr. Robert R. Redfield, will quickly decide whether to approve them. That will be the final step, after a review by the Food and Drug Administration and its own advisory committee on vaccines, before the first doses of vaccine are shipped nationwide.

A subgroup of the committee had already suggested that health care workers, who total about 21 million, should be the first to be vaccinated. On Monday, it recommended also including residents of long-term care facilities in that initial group. Next would be essential workers, then adults with high-risk medical conditions and those who are 65 or older.

Some of the questions the committee considered Monday included:

  • Whether people who have already had Covid-19 should not be vaccinated until there is ample supply. Dr. Robert Atmar, a committee member and infectious disease specialist at Baylor College of Medicine in Houston, said that “at the beginning, where it’s a resource-limited vaccine, my opinion is that we need to try and target as best we can to those that we know are susceptible.” But another committee member, Dr. Grace Lee, a pediatrics professor at Stanford University School of Medicine, pushed back, saying that much remains unknown about long-term immunity.

  • Whether essential workers like police, firefighters, teachers and transportation workers should be the second group to get the vaccine. “To me, the issue of ethics is very significant, very important for this country and clearly favors the essential worker group,” said Dr. Peter Szilagyi, a professor of pediatrics at the University of California, Los Angeles, noting that the group included a “high proportion of minority, low-income and low-education workers.”

Demonstrators protested ‘Stay Home, Stay Healthy’ orders in Washington State in April.
Credit…Ruth Fremson/The New York Times

Efforts to contain the coronavirus pandemic last spring quickly became politicized, forcing officials and citizens around the world to choose between public health and personal freedom. In the United States, the tension broke down roughly along ideological lines, with many blue states taking containment measures seriously, and red states less so.

In a new analysis, a team of researchers provided some of the first hard evidence of how the political divide drove behavior. The paper, posted Monday by the journal Nature Human Behavior, found that one measure of partisan hostility — the intensity of distrust and animosity toward the other side, red or blue — correlated both with people’s attitudes toward containment policies, and how they behaved.

The findings were based on interviews with more than 2,400 adults, conducted once in the summer of 2019 and again in April of this year.

The research team, led by James Druckman, a political scientist at Northwestern University, found that the average Democrat “is more worried, is more likely to have changed behaviors and is more supportive of policies to stop the spread of infections than the average Republican,” although there were substantial overlaps in attitudes.

The research team, which included scientists from the University of Arizona, Stony Brook University and the University of Pennsylvania, determined that in the hardest hit areas, these differences shrank. In effect, concern for personal and family safety blunted the effect of partisanship, as most everyone responded to the local outbreak.

“These findings have implications for understanding how best to combat COVID-19,” the authors concluded. Since partisan hostility underlies partisan gaps, “policymakers will need to devise different strategies to bring the parties together on these issues.”

Travelers at Miami International Airport on Sunday. Experts have been strongly discouraging holiday travel.
Credit…David Santiago/Miami Herald, via Associated Press

More travelers were screened at airport security checkpoints on Sunday than on any day since the pandemic took hold in March, a worrying sign that people flying to visit their families for Thanksgiving could increase the spread of the coronavirus.

A little more than one million people were screened by the Transportation Security Administration on Sunday, according to federal data published on Monday. That number is about half of what it was in 2019, but it represents a big increase from the spring, when less than a half a million people flew on any given day.

The Centers for Disease Control and Prevention and Dr. Anthony Fauci, the country’s top infectious disease expert, have been strongly discouraging holiday travel for fear that it would increase the number of new infections, which have surged in recent weeks as the weather turns colder and more people spend time indoors.

Airlines have said that flying is safe because of the precautions the industry has put in place, like high-end air filtration. They also point to the relatively few published cases of the coronavirus being spread during a flight. But the science on in-flight safety is far from settled, and travelers would still be at risk of contracting or spreading the virus at airports and once they are at their destination.

The increase in travel during the holidays has been encouraging for airlines. But it won’t be enough to offset the deep losses they have suffered during the pandemic. The nation’s largest airlines have collectively reported tens of billions of dollars in losses so far this year, and analysts expect demand to remain weak for a couple of years or more. The industry is hoping that the incoming Biden administration and Congress will give airlines more aid early next year.

Mallory Guy, right, used a translation app to communicate with her birth mother, Lim Mi-Soon.
Credit…Jun Michael Park for The New York Times

When a taxi deposited Mallory Guy in front of an apartment building in Cheonan, South Korea, after a 14-hour flight from Atlanta, a Korean couple was waiting for her with open arms.

It was the first time since she was 7 months old that Ms. Guy, 33, had been in the country where she was born. It was also her first time seeing her birth parents since she was sent to the United States more than three decades ago.

For some adoptees, birth family reunions had become a rite of passage. Then came the pandemic. The pilgrimages back to South Korea dwindled. Many adoptees canceled long-planned reunions after the government’s quarantine rules for foreign visitors made the trips too costly and time-consuming.

When Ms. Guy arrived in South Korea in September, she did not know whether she would be allowed to spend the two weeks at her biological parents’ home or be forced to stay at a costly government hotel. The South Korean Embassy’s website said only that such decisions were made on a case-by-case basis.

Her parents made Korean food for her and American snacks like peanut butter and jelly. (They also stocked up on milk, because they had heard that Americans love milk.) They even bought her an exercise bike, because she had told them during calls that she enjoyed using her Peloton.

After two weeks of immersion in her parents’ home, Ms. Guy took a coronavirus test, as mandated by the government, so she could leave quarantine and explore her home country with her family.

When a testing administrator asked her when she had last left the country for the United States, “I told her 1987, and she looked super-confused.”

The worker asked again, and Ms. Guy confirmed that she understood the question.

After telling her 1987 four more times, Ms. Guy said, “she finally wrote it down.”

Senator Kelly Loeffler of Georgia at an election event on Friday with the state’s other senator, David Perdue, and Vice President Mike Pence.
Credit…Tami Chappell/EPA, via Shutterstock

Senator Kelly Loeffler of Georgia, a Republican who is campaigning in a high-stakes runoff election that could determine control of the Senate, plans to get “back out on the campaign trail” after receiving her second consecutive negative coronavirus test, a campaign spokesman said on Monday.

This comes after Ms. Loeffler’s campaign on Sunday said she was isolating “out of an abundance of caution” after a series of coronavirus tests delivered mixed messages about whether she had contracted the disease.

According to Stephen Lawson, a campaign spokesman, a rapid test Ms. Loeffler took Friday morning came back negative, but a second test she also took that morning — a polymerase chain reaction, or P.C.R., test, which is considered more accurate — returned a positive result on Friday evening.

In between her receipt of the two conflicting test results, Ms. Loeffler attended campaign-related events on Friday, including a rally with Vice President Mike Pence and Senator David Perdue of Georgia, Mr. Lawson said.

Ms. Loeffler, 49, received another P.C.R. test on Saturday morning. But it was “inconclusive,” Mr. Lawson said of the results, which came in Saturday evening. On Sunday afternoon, Mr. Lawson issued another statement saying that the senator’s “previously inconclusive P.C.R. results were retested overnight and the results thankfully came back negative.” The negative result on Monday was also from a P.C.R. test.

He added: “Out of an abundance of caution, she will continue to self-isolate and be retested again to hopefully receive consecutive negative test results. We will share those results as they are made available. She will continue to confer with medical experts and follow C.D.C. guidelines.”

Ms. Loeffler notified those with whom she had sustained contact while she awaits further test results, he said.

Ms. Loeffler has held recent events with prominent Republicans, including Mr. Pence, Senator Tom Cotton of Arkansas and Mr. Perdue, who is also engaged in a runoff election that could determine control of the Senate. On Sunday, a campaign spokesman said Mr. Perdue was remaining at home until he had more details about the health status of Ms. Loeffler.

Mr. Perdue, 70, has encouraged people to wear masks to help stop the spread of the coronavirus. But he has also appeared at rallies where people did not wear masks. A Friday tweet from Ms. Loeffler includes a picture that shows the two senators in an indoor setting without masks.

A spokesman for Mr. Pence, Devin O’Malley, said also on Sunday that “as he awaits a confirmatory test from Senator Loeffler, Vice President Pence is in regular consultation with the White House Medical Unit and will be following C.D.C. guidelines as he has in other circumstances when he has been a close contact.”

The last time Mr. Pence was deemed a close contact was last month when his chief of staff, Marc Short, tested positive.

Mr. Pence continued to campaign then, with the White House saying that he was performing “essential” duties that exempted him from Centers for Disease Control and Prevention guidelines calling for people to quarantine for 14 days after exposure to the virus.

Ms. Loeffler, a businesswoman who is the Senate’s richest member, was temporarily appointed to her Senate seat late last year. She faces the Rev. Dr. Raphael G. Warnock, a Democrat, in an election on Jan. 5, when Georgia voters will also decide between Mr. Perdue and his opponent, Jon Ossoff, a Democrat.

Students in Karachi, Pakistan, on Monday.
Credit…Shahzaib Akber/EPA, via Shutterstock

ISLAMABAD, Pakistan — Pakistan announced Monday that schools across the country will close for six weeks beginning Nov. 26 as the government confronts a sharp rise in new coronavirus cases. The positivity rate was 7 percent in the past 24 hours with at least 34 deaths, health officials said, a worrying increase compared to the past several weeks.

Students will continue taking classes from home until Dec. 24, said Shafqat Mahmood, Pakistan’s federal education minister, during a news conference in Islamabad on Monday.

“All educational institutions will be opened on Jan. 11, 2021, after reviewing Covid-19 cases situation in the first week of January,” Mr. Mahmood said, noting that winter break for students would begin Dec. 25 and end on Jan. 10.

This is the second time Pakistan has closed schools, resorting to at-home learning back in March and only reopening classrooms in September.

“If we don’t make important decisions now, there is a possibility that the spread of the virus will overburden the health care system,” Dr. Faisal Sultan, the special assistant to the Pakistan prime minister on health, said Monday.

Pakistan was spared the kind of devastation that crippled other countries this past spring, and officials had expressed optimism that they were prepared for the second wave. But a new wave of infections has now raised concerns about the government’s ability to counter the virus.

To date, there have been more than 376,000 recorded cases of coronavirus and nearly 7,700 deaths, according to a Times database. The current daily average number of new cases in Pakistan stands at 2,557.

Health workers carried out flu vaccinations at a hospital in Milan, Italy, this month.
Credit…Andrea Fasani/EPA, via Shutterstock

After suffering through two big outbreaks of the coronavirus, many people in Italy greeted news that a vaccine could be available by early next year with some optimism.

But one of the country’s most renowned virologists and Covid-19 experts has provided a reality check about the country’s ability to carry out a mass vaccination drive.

He says he hasn’t even been able to get a simple flu shot.

“It’s a real scandal,” Dr. Massimo Galli, the director of the infectious disease department at the Sacco hospital in Milan, said Sunday on Italian television. He said that while he hoped the country would eventually be able to distribute a coronavirus vaccine to its citizens, the outlook was “ghastly.”

That Dr. Galli, who is 69 and among the most recognizable coronavirus experts in the country, could not get his hands on a simple flu vaccine renewed concerns about a potential lack of preparedness to procure and distribute coronavirus vaccines.

Flu shots are far less common in Italy than in the United States, but Italy’s health authorities had urged people to get them this year, both to keep healthy and to allow doctors to focus on Covid-19 patients.

But five months later, flu shots are few and far between, and millions of Italians, including older adults and patients with pre-existing conditions, haven’t been able to get them.

Some experts say that Italy’s regions, which control health care systems within their borders, placed their orders too late amid enormously high demand in the international marketplace. Regional authorities have instead attributed the shortage to delays by the providers.

In the hard-hit Serio valley in northern Italy, Dr. Mario Sorlini said a much higher than usual number of patients asked to be vaccinated for the flu. But the region only sent him about half the doses he received last year.

“We were the hardest hit province by Covid, and I was only able to do 25 percent of the flu vaccines I have to do,” Dr. Sorlini said, adding that if he and his colleagues did not receive the doses before the flu comes, it will be a “disaster on top of a disaster.”

The American Civil Liberties Union on Monday sued a meatpacking plant in Nebraska, alleging that it failed to take measures to prevent the spread of the coronavirus among workers and, as a result, also imperiled the surrounding community.

The lawsuit was filed against Noah’s Ark Processors, which operates a beef-processing plant in Hastings, Neb. Among the plaintiffs are former plant employees and a local pediatrician who has treated children of meatpacking workers as well as people infected with the coronavirus.

Noah’s Ark refused to take precautionary measures such as implementing physical distancing, distributing appropriate protective gear or conducting testing for the virus, according to the lawsuit. The plant also kept ailing workers on the job and forced them to wear masks soiled with blood, fat and sweat, the suit said.

The meatpacking plant declined to comment.

Often immigrants from Latin America, Asia and Africa, tens of thousands of workers in poultry- and meat-processing plants across the country have fallen ill from the virus and more than 220 have died. They typically toil in cold facilities, standing shoulder to shoulder on production lines and on kill floors.

In Nebraska, Hispanics comprise 11 percent of the population but accounted for 60 percent of coronavirus cases in July, according to data released by the state’s health department, because many of them work in the food-processing industry.

Despite legislative advocacy and numerous complaints, local, state and federal authorities have failed to require the establishment of safety standards in Nebraska’s meatpacking plants during the pandemic, according to the A.C.L.U., and there has been no significant enforcement action taken against any facility.

The lawsuit seeks a court order requiring that the plant implement four safeguards: physical distancing, clean masks, sick leave and testing. Attorneys with the A.C.L.U. said they hoped that the measures would serve as a baseline for facilities nationwide.

Spencer Amdur, a lawyer with the A.C.L.U.’s Immigrants’ Rights Project, said that Noah’s Ark had shown “shocking indifference” to its workers by failing to take “common-sense steps.”

“Every plant should be providing these basic protections,” said Mr. Amdur. “Without them, workers and others in the community face imminent and severe harm.”

Some restaurant owners in Los Angeles were upset about new restrictions because they had spent thousands of dollars creating outdoor dining areas.
Credit…Ryan Christopher Jones for The New York Times

Los Angeles restaurants, many already struggling since indoor dining was disallowed earlier this year, received another blow over the weekend when county health officials announced outdoor dining would also end for three weeks beginning on Wednesday.

While restaurants will still be allowed to do takeout and delivery, the timing of the new restrictions couldn’t be worse. The approaching holiday season is usually the busiest period of the year, when many restaurants make the money they need to survive the leaner months of January and February.

“Nothing will be the same,” the chef David Chang, the founder of the Momofuku restaurant group, which operates Majordomo in Los Angeles, wrote on Twitter. “Even if you survive until spring, it’s 3-5 months before tourism returns and office/corporate business will not come back as before.”

On Monday, restaurant owners and chefs scrambled to cancel Thanksgiving reservations while preparing to once again furlough employees.

The restaurant Castaway in Burbank had 625 reservations for Thanksgiving lunch and dinner, said John Tallichet, the chief executive of Specialty Restaurants Corporation, which had four restaurants offering outside dining in Los Angeles County.

While some of that food will be sold as Thanksgiving meals to go, Mr. Tallichet said much of it will go to the employees he will furlough for three weeks, if not longer. Before the pandemic, Castaway employed 200 people. That number has since dropped to 80 and will fall to around 10 employees as it shifts to a takeout business.

“I’m guessing we’re going to be shut down through the holidays,” he said. “Why allow us to operate for New Year’s and Christmas if they’re concerned now? So we’re taking that food and creating care packages for our employees to take home so at least they have a nice Thanksgiving meal.”

Some restaurant owners were upset about the new restrictions because they had spent thousands of dollars creating outdoor dining areas on sidewalks, parking lots and elsewhere with the belief that they would be allowed to continue serving customers that way.

“These restaurants have invested $30,000 to $50,000 in outdoor heaters and tents, being told all of this is allowable and safe and now they’re told, ‘nope, all of that investment was a waste,’” said Jot Condie, the president and chief executive of the California Restaurant Association, a trade organization representing the industry.

Restaurants all around the country are struggling with changing rules and consumer preferences as coronavirus cases rise. Last Friday, the New York restaurateur Danny Meyer announced that three of his restaurants, including Gramercy Tavern, would close for on-premises dining, but continue to offer takeout meals.

A gathering in Stamford, Conn., in June.
Credit…John Moore/Getty Images

As states struggle to contain the resurgent coronavirus, many officials are laying the blame on people gathering with family and friends. But are dinners and backyard barbecues really the engine driving the current surge of infections?

Household get-togethers undoubtedly do contribute to community transmission of the virus. But scientists say the available data do not support the contention that they are the main problem, scientists say.

Still, the idea has been repeated so often it has become conventional wisdom, leading to significant restrictions in many states. In dozens of statements over the past weeks, political leaders and public health officials have said that while previous waves of infection could be linked to nursing homes, meatpacking plants or restaurants, the problem now is that unmasked people are sitting too closely in kitchens and living rooms.

Most states don’t collect or report detailed information about the exposure that led to a new infection. But in states where a breakdown is available, long-term care facilities, food processing plants, prisons, health care settings and restaurants and bars are still the leading sources of spread, the data suggest.

The same cannot be said of smaller private gatherings with friends and family. In Colorado, only 81 active cases are attributed to social gatherings, compared with more than 4,000 from correctional centers and jails, 3,300 from colleges and universities, nearly 2,400 from assisted living facilities and 450 from restaurants, bars, casinos and bowling alleys.

“It seems like they’re passing off the responsibility for controlling the outbreak to individuals and individual choices,” said Ellie Murray, an epidemiologist at Boston University. “A pandemic is more a failure of the system than the failure of individual choices.”

Gov. Tim Walz of Minnesota on Wednesday took the extraordinary step of banning people from different households from meeting indoors or outdoors, even though evidence has consistently shown the outdoors to be relatively safe.

But the executive order allows places of worship, funeral homes and wedding venues — while they are encouraged to hold virtual events — to host as many as 250 people indoors.

Vermont likewise forbade people from meeting neighbors for a socially distanced and masked walk, but permitted them to dine indoors at restaurants before 10 p.m. (On Friday, following public complaints, Gov. Phil Scott of Vermont said people from different households could walk together as long as they wore masks and stayed more than six feet apart.)

These recommendations are unscientific and “bizarre,” said Dr. Ashleigh Tuite, an infectious disease modeler at the University of Toronto.

“If you’re an average person looking at what’s allowed and what’s not allowed, it may not make a lot of sense,” she said. “I can get together with nine of my best friends and sit around a table at a restaurant. So why can’t I do that in my house?”