At least three people who attended an election party at the White House last week, including the housing secretary and President Trump’s chief of staff, have tested positive for the coronavirus. Sseveral hundred people gathered at the event in the East Room for several hours, many of them not wearing masks as they mingled and watched election returns.

Ben Carson, the secretary of housing and urban development, tested positive for the coronavirus on Monday, according to a spokesman for the agency. He is the latest in a long list of administration officials, including Mr. Trump, to contract the virus.

Another is David Bossie, an adviser Mr. Trump recently appointed to be the face of his efforts to contest vote tabulations in states like Nevada and Georgia, two people familiar with the diagnosis said on Monday. Mr. Bossie tested positive on Sunday and told campaign officials of the result.

The third person from the election party is Mr. Trump’s chief of staff, Mark Meadows, who tested positive for the virus the day after the election, aides said, although Mr. Meadows tried to keep it quiet.

President-elect Joseph R. Biden Jr. made an urgent plea on Monday for Americans to wear masks to slow the spread of the virus, declaring that “a mask is not a political statement.” He said the pandemic would be his top priority when he replaces Mr. Trump on Jan. 20.

As the United States surpassed 10 million known cases on Sunday, the seven-day average of new cases across country rose to more than 111,000 a day, a record. By Monday evening, over 100,000 new cases had been recorded for the sixth consecutive day. Six states set daily records for new cases.

With the world anxiously awaiting any positive news about a pandemic that has killed more than 1.2 million people, the drug maker Pfizer announced on Monday that its coronavirus vaccine appeared to be robustly effective, based on an early analysis of trial results.

Mr. Carson, a neurosurgeon who ran unsuccessfully for the Republican presidential nomination in 2016, has defended Mr. Trump’s response to the virus and is a member of the White House virus task force.

At 69, Mr. Carson is at an elevated risk for complications. He is also a cancer survivor, having undergone surgery in 2002 for an aggressive form of prostate cancer.

“He is in good spirits and feels fortunate to have access to effective therapeutics, which aid and markedly speed his recovery,” Coalter Baker, the agency’s deputy chief of staff, said in an email. Mr. Baker did not specify which treatments Mr. Carson had received or would receive.

According to Armstrong Williams, a friend and personal adviser to Mr. Carson, the secretary felt ill over the weekend and was examined and tested early Monday at Walter Reed National Military Medical Center.

“I was just on the phone with him,” Mr. Williams said in an interview at midday on Monday. “He said he was feeling pretty bad over the last couple of days, but he was feeling a lot better now. Carson’s going to live. Carson’s going to be OK.”

Some patients who seem to fare well in the first week after diagnosis become seriously ill in the second week.

Mr. Carson’s wife, Candy, accompanied him to Walter Reed and was tested, but the results were not back yet, Mr. Williams said. It was not clear which kind of test each had taken.

The secretary was one of several hundred people at the White House party, according people with knowledge of the situation. But Mr. Williams said that Mr. Carson thinks he caught the virus before then, while campaigning for Mr. Trump by bus before Election Day. It was not immediately clear why Mr. Carson thinks so.

Five other White House aides and a Trump campaign adviser also tested positive in the days before and after Election Day, people familiar with the diagnoses told The Times on Friday.

President-elect Joseph R. Biden Jr. named Dr. Rick Bright, a former top vaccine official in the Trump administration who submitted a whistle-blower complaint to Congress, as a member of a Covid-19 panel to advise him during the transition, officials announced Monday.

Dr. Bright, who was ousted as the head of a federal medical research agency, told lawmakers that officials in the government had failed to heed his warnings about acquiring masks and other supplies. He said that Americans died from the virus because of the Trump administration’s failure to act.

“Lives were endangered, and I believe lives were lost,” Dr. Bright, the former director of the Department of Health and Human Services’s Biomedical Advanced Research and Development Authority, told a House subcommittee in May.

Mr. Biden’s decision to put Dr. Bright on his advisory panel is intended to send a signal that the incoming administration intends to confront the virus — which is surging across the country — in a very different way than President Trump, who sought to largely push responsibility onto states.

In a statement on Monday, Mr. Biden said the advisory board will help him shape his “approach to managing the surge in reported infections; ensuring vaccines are safe, effective, and distributed efficiently, equitably, and free; and protecting at-risk populations.”

After meeting with the board on Monday, Mr. Biden urged all Americans to wear a mask and vowed to make defeating the pandemic his No. 1 priority when he takes office on Jan. 20.

“It doesn’t matter your party, your point of view. We can save tens of thousands of lives if everyone would just wear a mask for the next few months,” Mr. Biden said.

On Sunday, the nation surpassed 10 million cases and sank deeper into the grip of what could become the worst chapter yet of the pandemic.

The rate of new cases is soaring: The seven-day average of new cases across the United States rose to more than 111,000 a day, as of Sunday. With 29 states setting weekly case records, the virus is surging in more than half the country. Nationwide, hospitalizations have nearly doubled since mid-September, and deaths are slowly increasing again.

The nation’s worsening outlook comes at an extremely difficult juncture: Mr. Trump, who remains in office until January, is openly at odds with his own coronavirus advisers, and winter, when infections are only expected to spread faster, is coming.

The three co-chairs of Mr. Biden’s virus advisory board are:Dr. Vivek H. Murthy, a former surgeon general, who has been a key Biden adviser for months and is expected to take a major public role; Dr. David A. Kessler, a former commissioner of the Food and Drug Administration who worked closely with Dr. Anthony S. Fauci, the nation’s top epidemiologist, to speed development and approval of HIV drugs; and Dr. Marcella Nunez-Smith, an associate professor of medicine and epidemiology at Yale University.

The 13-member panel will also include Dr. Ezekiel J. Emanuel, an oncologist and the chair of the department of medical ethics and health policy at the University of Pennsylvania. Dr. Emanuel is the brother of Rahm Emanuel, who served as White House chief of staff under former President Barack Obama
and as the mayor of Chicago. Dr. Emanuel has been a high-profile advocate of a more aggressive approach to the virus.

The other members of the panel are: Dr. Atul Gawande, a professor of surgery at Brigham and Women’s Hospital; Dr. Celine Gounder, a clinical assistant professor at the N.Y.U. Grossman School of Medicine; Dr. Julie Morita, the executive vice president of the Robert Wood Johnson Foundation; Dr. Michael Osterholm, the director of the Center for Infectious Disease Research and Policy at the University of Minnesota; Ms. Loyce Pace, the executive director and president of the Global Health Council; Dr. Luciana Borio, a National Security Council aide under Mr. Trump and acting chief F.D.A. scientist under Mr. Obama; and Dr. Robert Rodriguez and Dr. Eric Goosby of the University of California, San Francisco School of Medicine.

And Dr. Fauci said on Monday that he would stay at his post atop the National Institute of Allergy and Infectious Diseases after Mr. Biden’s inauguration, telling CNN that he has “no intention of leaving.”

“I’ve been doing it” — working in public health — “under six presidents,” Dr. Fauci said. “It’s an important job and my goal is to serve the American public no matter what the administration is.”

As coronavirus cases have surged to records across the United States, Gov. Philip D. Murphy of New Jersey laid out new restrictions for the state on Monday, calling for restaurants and nightclubs to shut down indoor service at 10 p.m. starting Thursday, and saying that no one may be seated directly at the bar.

High school sports teams are not permitted to participate in out-of-state tournaments, but college athletes may still travel.

Mr. Murphy said he would continue to consider additional targeted restrictions on nonessential businesses.

New Jersey’s seven-day average of coronavirus cases now exceeds 2,000 infections a day, or 24 per 100,000 people, the highest rate since May. Last week, the average rate of positive tests, a key indicator of a state’s control of the virus, reached 6 percent. Hospitalizations have also been rising, though death rates have not spiked.

Mr. Murphy, a Democrat, said in interview on CNBC’s “Squawk Box” on Monday that the new rules would be designed to “shave at the edges,” without imposing a full lockdown.

The new limits on businesses comes about two weeks after Newark, the state’s largest city, took similar action on its own to confront a hot spot centered in the Ironbound neighborhood, one of the state’s most thriving restaurant districts.

And in the New York City area, officials had also hoped to keep the outbreak at bay and press ahead with its slow but steady recovery from the dark days of spring. But now, its forecast is turning more alarming, too.

The number of new cases is swiftly rising, with more than 1,000 cases identified in New York City four days in a row this past week, or 12 per 100,000 people, a level that last occurred in May, according to a New York Times database.

Though new restrictions would be up to the governor, city health officials and Mayor Bill de Blasio’s aides have been discussing whether new citywide restrictions should be imposed, including a broader shutdown of nonessential businesses if the citywide seven-day average rate of positive virus test results climbs, and stays, above 3 percent. The figure was 2.21 percent, according to the city’s health department.

Hospitalizations and death rates are a small fraction of what they were at the height of the pandemic, and case count comparisons can be tricky, given that much more testing is occurring now. Around the state, the daily average of new cases for the last seven days was 2,757, or 14 per 100,000 people as of Sunday, according to the Times database.

What’s more, the positivity rate in New York City is still well below that in neighboring states.

Mr. de Blasio said on Monday that “now, unfortunately, we are seeing a real growth in the positivity rate in the city, and that is dangerous.”

He added, “This is my message to all New Yorkers: We can stop a second wave if we act immediately, but we have one last chance and everyone has to be a part of it.”

The city’s contact tracing program has disclosed few details about which trends and patterns are contributing to transmission. But one city health official, who spoke on condition of anonymity to share details from internal discussions, said clusters had been traced to workplaces, including construction sites and offices.

The mayor said that further lockdowns were possible should New York City not regain control of the virus.

“God forbid this continued and we had a full-blown second wave,” he said. “It means a lot more restrictions. Unfortunately, it could mean even having to shut down parts of our economy again.”

It could also mean having to close schools, he said.

The mayor has previously said that he favored halting indoor dining if the seven-day positivity rate reached 2 percent — a threshold that has already been crossed without his taking any action. On Monday, the mayor would only say that it was time to re-evaluate the wisdom of allowing limited indoor dining.

At his own news conference, Gov. Andrew M. Cuomo said the so-called red zone covering parts of Brooklyn was being downgraded to orange, which allows for less severe restrictions. Parts of Erie, Monroe and Onondaga counties would face greater restrictions, though, he said.

“This is going to be the constant for the foreseeable future,” Mr. Cuomo said, of his “whack-a-mole” approach to battling the virus. “Every couple of days we’ll say, ‘This place became a microcluster, this place is no longer a microcluster.’

The drug maker Pfizer announced on Monday that an early analysis of its coronavirus vaccine trial suggested the vaccine was robustly effective in preventing Covid-19, a promising development as the world has waited anxiously for any positive news about a pandemic that has killed more than 1.2 million people.

Pfizer, which developed the vaccine with the German drug maker BioNTech, released only sparse details from its clinical trial, based on the first formal review of the data by an outside panel of experts.

Pfizer said that the analysis found that the vaccine was more than 90 percent effective in preventing the disease among trial volunteers who had no evidence of prior coronavirus infection. If the results hold up, that level of protection would put it on par with highly effective childhood vaccines for diseases such as measles. No serious safety concerns have been observed, the company said.

Pfizer plans to ask the Food and Drug Administration for emergency
authorization of the two-dose vaccine later this month, after it has collected the recommended two months of safety data. By the end of the year it will have manufactured enough doses to immunize 15 to 20 million people, company executives have said.

Independent scientists have cautioned against hyping early results before long-term safety and efficacy data has been collected. Still, Pfizer is the first company to announce positive results from a late-stage vaccine trial.

Eleven vaccines are in late-stage trials, including four in the United States. Pfizer’s progress could bode well for Moderna’s vaccine, which uses similar technology.

The news comes just days after Joseph R. Biden Jr. clinched a victory over President Trump in the presidential election. Mr. Trump had repeatedly hinted a vaccine would be ready before Election Day, Nov. 3. This fall, Pfizer’s chief executive, Dr. Albert Bourla, frequently claimed that the company could have a “readout” by October, something that did not come to pass.

Both President Trump and President-elect Biden hailed the news on Monday.

Operation Warp Speed, the federal effort to rush a vaccine to market, has promised Pfizer $1.95 billion to deliver 100 million doses to the federal government, which will be given to Americans free of charge.

But in an interview, Kathrin Jansen, a senior vice president and the head of vaccine research and development at Pfizer, sought to distance the company from Operation Warp Speed and presidential politics, noting that the company — unlike the other vaccine front-runners — did not take any federal money to help pay for research and development.

She said she learned of the results from the outside panel of experts shortly after 1 p.m. on Sunday, and that the timing was not influenced by the election. “We have always said that science is driving how we conduct ourselves — no politics,” she said.

The data released by Pfizer Monday was delivered in a news release, not a peer-reviewed medical journal. It is not conclusive evidence that the vaccine is safe and effective, and the initial finding of more than 90 percent efficacy could change as the trial goes on.

In the wake of Joseph R. Biden’s victory and the latest optimistic reports about the effectiveness of Pfizer’s vaccine, Gov. Andrew M. Cuomo of New York once again assailed President Trump’s vaccine distribution plan, saying, “We can’t let this vaccination plan go forward the way the Trump administration is designing it.”

“The Trump administration is rolling out the vaccination plan and I believe it’s flawed,” Mr. Cuomo, a third-term Democrat, said on ABC’s “Good Morning America” on Monday. “They’re basically going to have the private providers do it, and that’s going to leave out all sorts of communities that were left out the first time when Covid ravaged them.”

Mr. Cuomo’s comments came even as he acknowledged that Pfizer’s results were “great news,” but some conservatives quickly accused the governor of trying to politicize the issue and hamper vaccine distribution efforts.

In a statement, Senator Ben Sasse, Republican of Nebraska, said: “After this nasty virus has killed hundreds of thousands of Americans and put millions out of work, it is beyond disgusting that Governor Cuomo would use a glimmer of hope for another worn-out ‘Trump is bad’ talking point. When we get a vaccine, we’re going to need all hands on deck distributing it as fast as possible. Shamelessly politicizing this is dangerous and stupid.”

For months, Mr. Cuomo has raised concerns about the White House’s vaccination strategy, claiming that the rush to develop a vaccine has become so politicized that people might have serious trepidations about a vaccine’s safety. As chairman of the National Governors Association, Mr. Cuomo has accused the federal government of not providing states with sufficient answers on how governors should prepare to distribute a vaccine.

Those concerns prompted Mr. Cuomo to announce in September a state task force that is supposed to review any vaccines authorized by the federal government before they’re distributed in New York. Last month, the governor released a draft plan outlining the broad contours of how the vaccine would be distributed in New York, where up to 40 million doses could be needed for the state’s 19 million residents. Mr. Cuomo said priority would be given to essential workers and those considered most vulnerable.

Mr. Cuomo has also said that relying on the private sector, including pharmacies, could leave out minority communities that have already been disproportionately affected by the virus.

While the plan isn’t finalized, a report released by the Department of Health and Human Services says that the most at-risk populations would indeed be prioritized in the initial phases of distribution, which will entail partnerships with local governments and public health sites, in addition to pharmacies, clinics, hospitals and nursing homes.

Ukraine’s president, Volodymyr Zelensky, said Monday that he has tested positive for the coronavirus, becoming the latest leader to contract the virus despite the extensive protective measures available to a head of state.

Mr. Zelensky, who is 42 and not known to have any of the underlying conditions that could put him at risk of developing severe illness from the virus, said in a post in English on Twitter that he felt “good” and was taking vitamins, adding, “it’s gonna be fine!”

The Ukrainian president said he intended to isolate himself but keep working. It was not clear if he had shown any symptoms. The president’s chief of staff, Andriy Yermak, has also tested positive, according to a statement he posted on Facebook minutes after the president’s tweet.

Cases have been shooting up in Ukraine. The country reported an average of 9,525 cases per day over the past seven days.

Mr. Zelensky has consistently urged Ukrainians to wear masks and to take other coronavirus precautions seriously. He often appears in public wearing a mask or on television conducting business by video conference.

Critics have, however, taken issue with a decision by his political party, which controls Parliament, to allocate more than half of a coronavirus relief fund intended for hospitals to road construction instead.

Mr. Zelensky, a former comedian, was elected president last spring and within months became entangl
ed in an American political scandal when President Trump requested, in a telephone call, that he investigate now President-elect Joseph R. Biden Jr. and Mr. Biden’s family.

Mr. Zelensky’s wife, Olena Zelenska, had a mild case of Covid-19 in June. At the time, Mr. Zelensky said he isolated for a time but tested negative.

It will be a while before the University of Notre Dame knows whether the boisterous on-field celebration following the football team’s double-overtime victory against top-ranked Clemson will cause a surge in students testing positive for the coronavirus.

But the school isn’t waiting to react. Faculty members and administrators are already debating stronger measures to prevent the virus from spreading as students take finals and go home for Thanksgiving.

Thousands of students leapt over brick walls, dashed past overwhelmed security guards and stormed the field on Saturday, gleefully mobbing the Notre Dame players and one another for more than 15 minutes and ignoring loudspeaker announcements to retreat.

In a letter to the student body Sunday night, the Rev. John Jenkins, the president of the university, called the “widespread disregard” of the school’s health and safety guidelines over the weekend “very disappointing,” and said there would be “zero tolerance” for noncompliance, either on campus or off. (A spokesman for the university said on Monday that Father Jenkins was not referring specifically to the football game, but to other gatherings.)

Any student who does not get tested for the coronavirus, or who leaves South Bend before the results are known, will not be allowed to graduate or register for next semester’s classes, he wrote.

But Father Jenkins’s credibility on campus is wearing thin. He has twice had to apologize for failing to wear a mask when he should have: posing for photos with returning students in August, and attending a White House reception where many attendees were infected, including him.

In an email Monday to the faculty and staff, Dan Lindley, associate director of the Notre Dame International Security Center, urged university leaders to lock down the campus for the rest of the semester (classes end Thursday, followed by final exams). His letter was in response to one Sunday night from the school’s provost and vice president saying the school would not shut down classes.

The crowd of 11,011 at the football game consisted almost entirely of students, university employees and players’ families. It will take several days, at least, before any infections caught at the stadium lead to symptoms or be detectable by tests. And Mark Fox, the deputy health director of St. Joseph County, Ind., who has been advising the university on pandemic response since August, said it may be difficult to definitively trace any new cases to the crush of students on the field.

GLOBAL ROUNDUP

Hungary and Portugal are the latest European countries to adopt new measures like curfews and limits on gatherings to curb rapid rises in new coronavirus cases.

Prime Minister Viktor Orban of Hungary said there would be a general curfew from 8 p.m. to 5 a.m., and that all public events would be banned, with family and private gatherings capped at 10 people. Restaurants will only offer delivery services and hotels will be limited to catering to business travelers.

High schools and higher education institutions will be moving to online classes, and dormitories will be closed, although nurseries, kindergartens, and primary schools will remain open. Sporting events will be held behind closed doors and gyms, indoor swimming pools, museums, theaters, and zoos will be closed.

The government will also extend some benefits, including payroll tax cuts and salary contributions, to the tourism and hospitality sector.

The new rules will need to be approved by Parliament, which is controlled by Mr. Orban’s party, and would be in place for 30 days.

Nearly 2,500 people have died after contracting the virus in Hungary since the start of the year, according to government figures, with three-quarters of the deaths occurring after Sept. 1. More than 114,000 people have tested positive for the virus in Hungary.

Portugal returned on Monday to a state of emergency that gives its government enhanced powers to impose lockdown measures to stop a second wave of Covid-19.

But the government has so far opted for relatively lenient restrictions compared to those introduced recently in some other European countries. As of Monday, about 7.1 million of the 10 million residents of Portugal must respect a nighttime curfew that runs from 11 p.m. to 5 a.m., as well as a stricter one during the coming two weekends, from 1 p.m. to 5 a.m.

The government said it would review the situation after Nov. 23 before deciding whether to extend the state of emergency.

On Friday, the country registered 5,550 new Covid-19 cases, the highest daily figure since the pandemic started. The number of patients in Portugal’s intensive care units has also climbed this month to over 300, which is more than at the peak in April.

In Andalusia, the southern region of Spain that borders Portugal and is home to about 8.4 million inhabitants, the regional authorities have ordered residents to remain within their municipalities.

Bars and restaurants must close at 6 p.m., except in the province of Granada, where establishments must remain fully shuttered because of the high infection rate. Andalusia now has 457 Covid-19 patients in intensive care units, which is also a record since the start of the pandemic last March.

In other news around the world:

• German states are preparing to distribute coronavirus vaccines when they become available by setting up 60 decentralized centers across the country to provide fast and efficient access to doses.

• A new partial lockdown to contain the spread of the coronavirus in France is having a smaller impact on the national economy than a total lockdown earlier this year, the French central bank said Monday. France’s second lockdown, which began Oct. 17 and is now expected to stretch beyond Dec. 1, was aimed at minimizing damage to the economy just as an economic recovery was starting to take hold during a summer rebound.

• A 51-year-old air cargo worker has been infected with the coronavirus in Shanghai, China’s biggest city, prompting an immediate effort to contain the virus before it can spread. The Shanghai municipal government ordered the immediate quarantine of close contacts of the worker and restricted travel for anyone living in Yingqian, the village within Shanghai where the worker lived.

• As of Monday, Taiwan had not yet received an invitation to join the World Health Assembly meeting, which will end on Saturday, according to a spokeswoman for Taiwan’s foreign ministry, despite a multilateral effort led by the United States to support the island’s bid for observer status. Taiwan has won international praise for its success in controlling a virus that has sickened more than 50 million people and killed more than 1.2 million around the world: Taiwan.

Since the start of the fall semester, most universities have planned to end in-person classes before Thanksgiving and require students to finish the term remotely, partly to avoid an expected wave of cold-weather infections. That means that in a couple of weeks, hundreds of thousands of students will be crisscrossing the country by
plane, train, bus and car, streaming back to hometowns until the spring semester begins.

So what are colleges and universities doing to reduce the chances that those students might carry the coronavirus with them?

As has been true with so much of the nation’s response to the pandemic, the answer is a patchwork of policies, with a minority of schools mandating that students test negative on coronavirus tests before they can leave campus — and many more offering little more than optional testing and advice.

For example, Indiana University in Bloomington — where dozens of fraternity and sorority houses had to quarantine in September — will open its weekly surveillance testing to all of the 42,000 students living on or near campus. But the testing will be voluntary for most.

The University of Michigan — where infections recently spiked so severely that local health officials issued a stay-in-place order — will make exit tests mandatory for some 5,000 undergraduates in university housing, but voluntary for thousands more living off-campus.

A smaller number of schools are insisting on exit testing.

New York State’s university system will require “all students using on-campus facilities in any capacity” to test negative for the virus within 10 days of their departure, and to quarantine according to county health rules if they test positive, whether they are on or off-campus. The plan will entail testing about 140,000 students at SUNY’s 64 colleges and universities.

And in Massachusetts, where cases have been surging, Boston University has asked students not to leave campus, period, until Dec. 10, when classes end. “We are saying, ‘Stay here,’ plain and simple,” Kenneth Elmore, the associate provost and dean of students, said.

“There’s a responsibility not to unleash little ticking time bombs,” said A. David Paltiel, a professor of health policy and management at the Yale School of Public Health, noting that recently exposed students can feel well and still shed large quantities of the virus. “But this has not yet hit the radar screen of many college administrators.”

The American College Health Association, which represents college health officers, issued public health guidelines last week recommending that schools encourage students to get tested before their Thanksgiving departure, refrain from traveling if they test positive and quarantine for 14 days at home upon arrival. But the association stopped short of calling for mandatory testing.

The New York Times has documented more than 252,000 coronavirus cases and at least 80 deaths on college campuses since the pandemic began. Most of the deaths involved college employees in the spring. But at least four students — most recently, Bethany Nesbitt, a 20-year-old student at Grace College in Indiana — have died this semester after contracting Covid-19.

Julie Halpert contributed reporting.

• Stocks on Wall Street fell short of a record on Monday, as a late retreat pulled back a soaring market.

• A relief-fueled rally had lifted the S&P 500 by as much as 3.9 percent earlier in the day, after the pharmaceutical giant Pfizer said early data showed that its coronavirus vaccine appeared 90 percent effective. The announcement followed news on Saturday that Joseph R. Biden Jr. had enough votes in the Electoral College to clinch the presidency, a sign that the American vote, which some investors had worried could spiral into a chaotic period if President Trump lost, appeared to proceed more or less normally.

• But the S&P 500 ended up just 1.2 percent by the end of trading, short of its Sept. 2 record. The Dow Jones industrial average rose about 3 percent.

• The largest technology stocks, seen both as safe bets during the economic crisis and beneficiaries of a work-and-play-from-home environment during the pandemic, were sharply lower and helped drive the late pullback. Amazon fell 5 percent, Apple was 2 percent lower, and Microsoft fell more than 2 percent. The Nasdaq composite fell 1.5 percent.

• Pfizer said a vaccine it was developing with BioNTech was found to have been more than 90 percent effective in preventing Covid-19 infections, based on a large study. Pfizer said that by the end of the year it will have manufactured enough doses of the vaccine to immunize 15 million to 20 million people.

• Scientists have cautioned against hyping early results before long-term safety and efficacy data has been collected, and no one knows how long the vaccine’s protection might last. It’s also likely to be months before Pfizer’s vaccine or any other is able to substantially curb the coronavirus outbreak, which is picking up steam around the world.

• That caution was lost on investors, who rushed into investments that would benefit from a world returning to some semblance of normalcy, and out of stocks that have become winners in the pandemic.

• “Hurdles still remain,” said Karen Ward, a strategist at JPMorgan Asset Management. “We need to find out more about production capabilities, rollout and takeup. But for now, this is shifting the winners and losers.”

• Among the winners: American Airlines rose about 15 percent and United Airlines rose about 19 percent. Carnival, the cruise ship operator, rose 39 percent. Also sharply higher were the shopping center owners Simon Property Group and Kimco Realty, the concert promoter Live Nation and the office-building owner Vornado Realty Trust.

• And those whose businesses have been well suited under lockdowns and stay-at-home orders struggled. Peloton Interactive dropped 20 percent, while Netflix fell 8.6 percent, for example.

• Over all, though, it was a global rally. The benchmark Stoxx Europe 600 index surged 4 percent, its biggest one-day gain since March, while the FTSE 100 in Britain rose 4.7 percent. In Asian markets, which closed before Pfizer announced its news, the Nikkei 225 in Japan ended the day 2.1 percent stronger, and the Hang Seng Index in Hong Kong finished up 1.2 percent.

• Crude oil prices also leapt about 9 percent, to more than $40 a barrel. Prices for government bonds — where investors traditionally park funds during times of uncertainty — tumbled sharply.

• Trading on Monday followed the best week for the S&P 500 since April, as investors became more convinced that President-elect Biden would govern alongside a Re
  publican-held Senate. However, two runoff elections in Georgia mean the control of the Senate will not be known until January.

Caught between the surging pandemic on the one hand, and political pressure to keep schools and businesses open on the other, many state governors have been trying to walk a fine line lately, by strongly urging mask-wearing and other precautions without mandating them.

But the governor of Utah said on Sunday that he had to step over that line, and others may soon do the same.

“Due to the alarming rate of Covid infections,” Gov. Gary Herbert, a Republican, wrote on Twitter, he was announcing a new state of emergency, including a mask mandate that would apply statewide. Social gatherings would be limited to “household only” for the next two weeks, he wrote, and all extracurricular activities at schools would be put on hold.

He emphasized that the measures were “not shutting down our economy, but are absolutely necessary to save lives and hospital capacity.”

Since Election Day, some states have shifted toward taking additional steps to rein in the virus, or have signaled that such action may be coming.

Denver installed a “Home by 10” order on Sunday evening, instructing people to remain in their homes between 10 p.m. and 5 a.m, except for essential activities. The order also prohibits “all public and private gatherings” between people from different households at all times.

The mayor of Denver, Michael B. Hancock, warned that “there’s another stay at home order in our future” if the spread of the virus does not slow. The daily average of cases in Colorado has increased by 114 percent over the past two weeks, according to a New York Times database.

The order is set to expire at 5 a.m. on Dec. 7, though gatherings on Thanksgiving Day will be exempt. People who violate the order face a fine of up to $999.

On Friday, Gov. Mike Dunleavy of Alaska extended his state’s emergency declaration for another 30 days, and Gov. J.B. Pritzker of Illinois warned that a new stay-at-home order may be necessary if the virus’s spread in the state does not slow soon.

In New Jersey, Gov. Philip D. Murphy said he planned to announce some tightening of the state’s restrictions on Monday, perhaps including limits on restaurant hours and bar seating, without imposing a full lockdown.

President-elect Joseph R. Biden Jr., who has called for the whole nation to be under a mask mandate, announced the creation of a coronavirus advisory board on Monday to get started on his administration’s pandemic response policies.

Utah, which has recently been reporting an average of more than 2,000 new coronavirus cases a day over the last week, is one of a number of states in the Great Plains and Mountain West where hospitals are rapidly filling to crisis levels. The Salt Lake Tribune reported on Sunday that 424 Utahns were hospitalized with Covid-19, a record for the state and an increase of nearly 25 percent from a week earlier. In neighboring Idaho, one of the state’s largest hospitals had to turn away patients over the weekend for lack of space, The Idaho Statesman reported.

“In my 11 years as governor, I have seen Utahns do remarkable things,” Governor Herbert wrote in his announcement Sunday night. “We have overcome extraordinary challenges and great adversity. I implore you now to do all you can to stop the spread. It is time for Utahns to unite in this response and bring healing back to our state.”

The 2020 calendar promised an especially notable Veterans Day, marking 75 years after World War II ended and 70 years after the Korean War began. But just as the pandemic changed the calculus for the more joyful holidays of summer, so too is it upending plans for the more somber holiday this week that commemorates those who served the nation in wartime.

Many cities around the country have canceled events; others plan to hold them virtually. Here is how some of the country’s prominent observances are being affected.

The annual wreath-laying ceremony at Arlington National Cemetery will take place at 11 a.m. Eastern on Wednesday, and will be streamed live online. The cemetery will be open to the public that day, with masks required, but the Memorial Amphitheater and the Tomb of the Unknowns will be closed. At several veterans’ cemeteries in Maryland, ceremonies will take place with attendance limited to 250 people.

Philadelphia, which held its Veterans Day events over the weekend, went entirely virtual. Birmingham, Ala., whose annual parade is believed to be one of the nation’s oldest, canceled in-person events in favor of a virtual parade and fireworks display; organizers said it was the first time they had done so.

In New York, which usually holds one of the nation’s largest commemorations, organizers said a 120-vehicle motorcade would follow the regular parade route down Fifth Avenue on Wednesday carrying representatives of the groups that usually march, while online, a virtual “line of march” displays profiles of participants. Veterans’ motorcycle clubs would also ride the route, and small, socially distanced wreath layings would be held throughout the city, according to the United War Veterans Council in New York.

Some cities, like Las Vegas, canceled their events entirely. Others planned to hold Veterans Day 5K runs, fireworks and parades, and place flags on grave sites, with social distance precautions and fewer attendees.

Though many colleges have had significant virus outbreaks or imposed tight restrictions on their campuses to stave off infection, some schools, like Wichita State University and Missouri State University, said they would welcome veterans to on-campus commemorations or make the events viewable online.

The pandemic has turbocharged profits at some big businesses, like Amazon, which reported a 70 percent increase in earnings in the first nine months of the year. But it has devastated others, like Delta Air Lines, which lost $5.4 billion in the third quarter.

Perhaps most surprising: Some companies that had feared for their lives in the spring, among them some rental car businesses, restaurant chains and financial firms, are now doing fine — or even excelling.

Wall Street analysts expect earnings to rebound to a record high next year. And, over all, 80 percent of companies in the S&P 500 stock index that have reported third-quarter earnings so far have exceeded analysts’ expectations, said Howard Silverblatt, senior index analyst for S&P Dow Jones Indices.

As the pandemic forced people to stay home and do more things online, some successful companies, like Amazon, were perfectly positioned to take advantage of the change. Now, these businesses are becoming even more dominant.

Tech companies were strong before the pandemic downturn — and have powered through the rout, which could help the economy recover faster this time, said Jonathan Golub, chief U.S. equity strategist at Credit Suisse Securities.

But the outlook is dire for other businesses.

Passenger airlines are among the biggest losers of the pandemic, and they have few options to improve their prospects. Delta, United Airlines and American Airlines worked quickly to cut costs and got $50 billion in the March federal stimulus package.

Still, investors are not all that worried, and are signaling that they expect a broad profits recovery among the largest U.S. companies. The S&P 500 has soared nearly 57 percent from its March low and is up 8.6 percent for the year.

Those gains may seem odd given that the combined profits of the companies in that index are on track to decline 25 percent this year from a record showing in 2019. But a big chunk of that rally can be attributed to a handful of technology stocks.

Of course, many struggling businesses, including lots of restaurants, stores and services companies, are not traded on the stock market. That means a surge in stock prices can give a misleadingly optimistic view of where the economy is headed.