New York City’s public school system will shutter on Thursday, the schools chancellor, Richard A. Carranza, wrote in an email to principals, in a worrisome signal that a second wave of the coronavirus has arrived. Schools have been open for in-person instruction for just under eight weeks.
“As of this morning, November 18, the City has now reached this threshold of test positivity citywide and, as a result, the DOE will temporarily close down all public school buildings for in-person learning, Thursday, November 19,” Mr. Carranza wrote shortly after 2 p.m. on Wednesday, about four hours after Mayor Bill de Blasio was scheduled to give a news conference. Mr. de Blasio confirmed the news in a tweet.
The shutdown — which was prompted by the city reaching a 3 percent test positivity rate over a seven-day rolling average — is perhaps the most significant setback for New York’s recovery since the spring, when the city was a global epicenter of the outbreak.
It was also a major disappointment for Mayor Bill de Blasio, who was the first big-city mayor in the country to reopen school buildings. Moving to all-remote instruction will disrupt the education of many of the roughly 300,000 children who have been attending in-person classes and create major child care problems for parents who count on their children being at school for at least part of the week.
Virus transmission in city schools had remained very low since classrooms reopened at the end of September, and the spike in cases does not appear to be caused by the reopening of school buildings.
Still, as the city chose to end in-person learning, indoor dining and gyms will remain open at a reduced capacity. Nonessential workers can continue to use public transportation to commute to offices.
That dynamic has infuriated parents run ragged by fluctuating school schedules and frustrated public health experts who have been pushing for more in-person instruction. It has also led to calls for the mayor and Gov. Andrew M. Cuomo to make keeping classrooms open their highest priority.
New York is home to the nation’s largest school system, with 1,800 schools and 1.1 million students. The city’s public school families, the vast majority of whom are low-income and Black or Latino, have endured roughly eight months of confusion about whether and when schools would be open or closed.
Mr. de Blasio had put school reopening at the center of his push to revive the city, and he has repeatedly said that remote learning is inferior to classroom instruction. But many teachers and parents have said that the city has not done nearly enough to improve online learning.
Case numbers are rising so quickly in New York that more restrictions appear likely. Mr. de Blasio has said that indoor dining should be reassessed; only Mr. Cuomo has the authority to close indoor dining rooms.
At a news conference on Wednesday, Mr. Cuomo said that he would shut down indoor dining in the city and impose other restrictions once the state’s data showed that the city had reached a 3 percent test positivity rate over a seven-day rolling average.
On Wednesday, the state’s health data showed that the city had a seven-day rolling average of 2.5 percent. Over the course of the pandemic, the city’s health department’s numbers have often differed from the state’s.
Meeting the 3 percent threshold would qualify the city to be an “orange” zone, the second level of restrictions under the state’s color-coded tier system, which applies different limits in regions of the state where the virus is surging more severely than others.
Parts of the city where cases have risen in recent weeks have been subject to more restrictions, but officials have declined to impose restrictions across all five boroughs.
On Wednesday, Mr. Cuomo also said that parts of the Bronx would be placed into a “yellow zone” and that the state would expand the existing yellow zone in Queens. In those zones, open schools must conduct weekly testing of students and staff, gatherings are limited to 25 people and houses of worship are limited to half their capacity.
Statewide, New York reported a seven-day average positivity test rate of 2.88 percent, and 2,202 people were hospitalized, Mr. Cuomo said.
In the state’s orange zones, all schools, private and public, are required to close and shift to remote learning. Under the state’s plan, schools must remain closed for at least four days and are allowed to reopen if they meet certain testing criteria.
In orange zones, some nonessential businesses deemed high risk, such as gyms and personal-care services, are also required to close. Indoor dining must end, and restaurants with outdoor dining can serve no more than four people at a table. Houses of worship are limited to 25 people or 33 percent capacity, and all mass gatherings are limited to 10 people. Gatherings at private residences are also limited to 10 people statewide.
The state added new restrictions to parts of Western New York, where Mr. Cuomo said the positivity rate was 5.1 percent. Parts of Erie County, which encompasses Buffalo, will be moved into an orange zone; other parts of the county and parts of neighboring Niagara County will become a yellow zone.
The Food and Drug Administration on Tuesday gave an emergency green light to the first rapid coronavirus test that can run from start to finish at home, paving a potential path for more widespread testing outside of health care settings.
The test, developed by the California-based company Lucira Health, requires a prescription from a health care provider. People under the age of 14 also can’t perform the test on themselves. But with a relatively simple nasal swab, the test can return results in about half an hour, and is projected by the company to cost $50 or less, according to the product’s website. Clinicians can also run the test on their patients, including children under the age of 14, potentially delivering answers during a single visit to a care center or pharmacy, instead of routing a tough-to-collect sample through a lab.
A handful of other tests have been cleared by the F.D.A. for at-home collection of samples, which are then shipped to a lab for processing. But Lucira’s test is the first to remove the need for an intermediary.
“Today’s authorization for a complete at-home test is a significant step toward F.D.A.’s nationwide response to Covid-19,” Jeff Shuren, director of the F.D.A.’s Center for Devices and Radiological Health, said in a statement. “Now, more Americans who may have Covid-19 will be able to take immediate action, based on their results, to protect themselves and those around them.”
People who test positive for the coronavirus are expected to isolate themselves from others for 10 days from the day their symptoms started, or the day they tested positive, per guidelines from the Centers for Disease Control and Prevention.
Laboratory tests that look for the coronavirus’s genetic material using a technique called polymerase chain reaction, or P.C.R., are still considered the gold standard for detecting the virus. But the new at-home test relies on similar principles by using a method called a loop mediated amplification reaction, or LAMP. Like P.C.R., LAMP repeatedly copies genetic material until it reaches detectable levels, making it possible to identify the virus even when it is present at only very low levels in the respiratory tract. While faster and less cumbersome than P.C.R., LAMP is generally thought to be less accurate.
People taking the battery-powered test must swirl a swab in both of their nostrils, then dip and stir the swab into a vial of chemicals. That vial is then plugged into a test cartridge that processes the sample. Within half an hour, the test cartridge will light up as “positive” or “negative.” Federal guidelines note that people taking the test should report the results to their health care providers, who must then inform public health authorities to help track the virus’s spread.
According to the product’s instructions, Lucira’s LAMP test was able to accurately detect 94 percent of the infections found by a well-established P.C.R. based test. It also correctly identified 98 percent of the healthy, uninfected people.
The study, which was conducted by the company, was small, and included only people who had symptoms of Covid-19, the disease caused by the coronavirus. The packaging for the test notes that it “has not been evaluated” in asymptomatic people.
One day after the governor of California announced that the state was “pulling the emergency brake” on its reopening and reinstating broad restrictions, Los Angeles County went a step further on Tuesday and announced a curfew for businesses.
Starting Friday, restaurants, breweries, bars, wineries and nonessential retail establishments must close from 10 p.m. to 6 a.m. A similar move is being considered statewide.
“This is a different kind of moment, a new level of danger,” Mayor Eric Garcetti said on Monday before the new measures were announced. “If we don’t make these decisions now, there really is only one outcome: We will almost certainly have to shut things down again. And more people will get sick and die.”
The moves in California came as state and local leaders across the United States try to slow the coronavirus, which has killed nearly 250,000 Americans and is now setting daily records for the number of people hospitalized with the disease. On Wednesday morning, that number stood at 76,823, according to the Covid Tracking Project.
Dr. Anthony S. Fauci, the government’s top infectious disease expert, said on Tuesday that the nation needed “a uniform approach,” instead of a “disjointed” state-by-state, city-by-city response.
But that is not what is happening. Like in the spring, when the country failed to develop a coordinated national response, a patchwork of measures is being put in place to combat the virus. Public health experts say the lack of a national strategy has been a primary reason for the country’s world-leading caseload and death toll.
Unlike in the spring, the virus is now spreading much more widely, exacting a deadly toll in communities from coast to coast. On Tuesday, more than 1,580 new deaths were reported nationwide, the highest single-day total since mid-May. Five states set single-day records for new deaths.
In the past two days, Ohio announced a nightly curfew, and Mississippi extended a mask mandate to seven more counties. Iowa will issue its first statewide mask order, Maryland will order all bars, restaurants and night clubs to close by 10 p.m., and Pennsylvania will require anyone who enters the state to be tested before arrival.
In Illinois, Gov. J.B. Pritzker said that, starting Friday, the entire state would move to Tier 3 under its mitigation plan, which limits the number of customers at many businesses and restricts private indoor gatherings to people in the same household, among other measures. Casinos and indoor venues like theaters and museums must close, and outdoor group activities will be limited to 10 people.
In Maryland, Gov. Larry Hogan announced that, beginning Friday, all bars, restaurants and night clubs would have to close by 10 p.m. and businesses, religious institutions and organizations would be limited to 50 percent of capacity.
In Mississippi, where Gov. Tate Reeves lifted a statewide mask mandate in September, new extensions in parts of the state meant that masks were only required in 22 counties out of 82.
Gov. Mike DeWine of Ohio, a rare Republican leader of a red state who has consistently bucked President Trump’s opposition to tough restrictions, announced that his state would be under a curfew from 10 p.m. until 5 a.m. for three weeks starting on Thursday.
Ohio has reported a daily average of more than 7,000 new cases over the past week, seven times as many as in early October and more than at any time since the pandemic began. “These are astronomical numbers,” the governor said at a news conference on Tuesday, urging residents to wear masks and maintain strict social distancing until a vaccine is widely available.
Mr. DeWine said all retail businesses would have to close during the curfew and that residents should stay home unless they are commuting to work or traveling for emergency purposes. He called the rules “common sense.”
In the past week, the United States has reported a daily average of nearly 160,000 new coronavirus cases. The virus is overwhelming health systems and killing more than 1,100 Americans a day. But there is a slender silver lining: It is hastening the testing of vaccines that could eventually end the pandemic.
The surging virus has already allowed the drugmakers Pfizer and Moderna to accelerate the testing of their vaccines, which appear to be very effective at preventing Covid-19.
In late-stage vaccine trials, the faster that participants get sick, the faster that drug developers gain enough data to know whether their vaccines are effective.
Pfizer said on Wednesday that its coronavirus vaccine was 95 percent effective and had no serious side effects — the first set of complete results from a late-stage vaccine trial as Covid-19 cases skyrocket around the globe.
Moderna announced on Monday that an early analysis had found its vaccine to be 94.5 percent effective. The company had planned on needing only 53 cases of Covid-19 to turn up in its trial before experts would take a first look at the data. But the nationwide surge in infections helped Moderna blow past that number: The results were based on 95 sick participants.
The fast-growing pandemic could also speed up trials of treatments for Covid-19.
The drug company Regeneron, for example, is testing the antibody treatment that President Trump received after he caught Covid-19. A company spokeswoman said enrollment in its trial has accelerated slightly this month.
Even if the grim situation in the United States ultimately helps vaccines and treatments become available sooner, the country would have been much better off if it had kept the pandemic under control, public health experts said.
“This is not how anyone would want it to play out,” said Natalie Dean, a biostatistician and an expert in vaccine trial design at the University of Florida. “I’d rather be South Korea,” which has kept the virus at bay since early in the year, she said.
Hundreds of health care workers at the Mayo Clinic have become infected with the coronavirus, even as the prestigious hospital system is treating rapidly growing numbers of patients with Covid-19.
“All of our hospitals are really stretched,” Dr. Amy Williams, who leads the hospital system’s response to Covid-19, said in a news conference on Tuesday. “Many are absolutely full at this time.”
At its flagship hospital in Rochester, Minn., Covid patients occupied all 32 beds in the medical intensive care unit, she said, and the hospital was adding another dozen beds to cope with the inflow of seriously ill patients expected in the next few weeks.
Staffing has emerged as a critical issue, Dr. Williams said. “We are most concerned about not being able to care for patients because of the decrease in our staff due to Covid-19 reasons, whether it is they are exposed and they’re out on quarantine, they’re taking care of a family member who has Covid-19 or they have been infected themselves,” she said.
In the last two weeks alone, about 900 employees have received a Covid diagnosis in Rochester, in the system’s 20 community hospitals in Wisconsin and Minnesota, or in the outpatient clinics it operates there. Both states are experiencing sustained surges in cases that are far worse than at any previous time in the pandemic. with Minnesota reporting nearly 6,000 new cases on Tuesday.
Most of the infections among the Mayo Clinic staff have occurred from community spread, Dr. Williams said, while a few have been traced to exposure from other employees when eating together unmasked. “We’re really not seeing exposures from patient to staff,” she said.
With about 1,500 of its 55,000 employees in the Midwest now sidelined because of the virus, the organization is asking recently retired nurses to come back to work; relocating nurses from its facilities in Arizona; and shifting nurses from other aspects of its operations, like research, to help care for patients. The Mayo hospital system have also cut back on the number of nonessential procedures it is performing.
For months, Gov. Kim Reynolds of Iowa saw little need to intervene in the choices of Iowans, who she insisted could make their own decisions about whether to wear a mask to protect against a dangerous pandemic.
But as the virus ravaged her state and hospitals filled to the brink, Ms. Reynolds abruptly reversed herself this week and began requiring that masks be worn indoors when the wearer will be close to another person for more than 15 minutes.
She joined a wave of Republican governors who are newly, and at times reluctantly, wielding the power of their offices to require coronavirus precautions as the erupts to crisis levels across the United States.
“No one wants to do this,” Ms. Reynolds said in a live address to Iowa, which now has the third-highest rate of new cases in the nation relative to its population. “I don’t want to do this.”
Interviews with more than a dozen political, health and business leaders in Iowa — including some the governor consulted before issuing the order — show that her hand was forced by a spiraling hospital crisis. As pressure built from doctors, mayors and even people in her own administration, the message was clear: If she did not act, Iowa’s hospitals could soon be overflowing with coronavirus patients.
More than 4,100 people are newly testing positive for the virus in Iowa each day on average, an 86 percent increase from two weeks ago. Hospitalizations have doubled in the same period, and coronavirus patients now account for one out of four people admitted to hospitals in the state.
“What has really changed in the last couple of weeks is the hospitalization rate,” said Suresh Gunasekaran, chief executive of the University of Iowa Hospitals and Clinics, describing his regular discussions with the governor, her aides and health officials in the state. “I think that was what really persuaded the whole state, including the governor.”
The drugmaker Pfizer said on Wednesday that its coronavirus vaccine was 95 percent effective and had no serious side effects — the first set of complete results from a late-stage vaccine trial as Covid-19 cases skyrocket around the globe.
The data showed that the vaccine prevented mild and severe forms of Covid-19, the company said. And it was 94 percent effective in older adults, who are more vulnerable to developing severe Covid-19 and who do not respond strongly to some types of vaccines.
Pfizer, which developed the vaccine with its partner BioNTech, said the companies plan to apply to the Food and Drug Administration for emergency authorization “within days,” raising hopes that a working vaccine could soon become a reality.
The trial results — less than a year after researchers began working on the vaccine — shattered all speed records for vaccine development, a process that usually takes years.
If the F.D.A. authorizes the two-dose vaccine, Pfizer has said that it could have up to 50 million doses available by the end of the year, and up to 1.3 billion by the end of next year.
However, only about half of its supply will go to the United States this year, or enough for about 12.5 million people — a sliver of the American population of 330 million. Americans will receive the vaccine free of charge, under a $1.95 billion deal the federal government reached with Pfizer for 100 million doses.
Federal health officials have said the first doses of the vaccines will likely go to groups like health care workers who are at high risk for exposure, as well as people who are most vulnerable to the disease, such as older people.
The results align with an early analysis that Pfizer and BioNTech reported last week, which found that the vaccine was more than 90 percent effective. Then on Monday, the drugmaker Moderna reported that its vaccine was 94.5 percent effective in an early analysis.
Dr. Saad Omer, the director of the Yale Institute for Global Health, said the results showing the vaccines protected people from severe disease was good news, because with such limited availability initially, the first goal will be not to stop transmission of the disease, but to prevent people from becoming extremely ill. “So that is very reassuring,” he said.
If the vaccine is authorized, attention will immediately shift to how it will be distributed. The vaccine must be stored at minus 94 degrees Fahrenheit, colder than any other vaccine in development. Pfizer will ship the vaccine in special boxes of 1,000 to 5,000 doses that are stuffed with dry ice and equipped with GPS-enabled sensors.
Even as France became the first country in Europe to pass two million detected cases of coronavirus infection this week, authorities expressed optimism that weeks of restrictions on movement and social interactions were starting to slow the spread of the virus.
“Our collective efforts are starting to bear fruit,” Jérôme Salomon, a top health ministry official, said at a news conference on Tuesday.
Still, French officials warned that lockdown restrictions would have to remain in place for at least several more weeks. France recorded more than 45,000 new cases over the previous 24 hours, bringing the country’s total to 2,036,755.
The number of hospitalized Covid-19 patients peaked at nearly 33,500 this week — slightly more than during the first wave last spring — and the pressure on French hospitals is still “very strong,” Mr. Salomon said.
Over 46,000 deaths have been tied to the virus in France.
France last month became one of the first countries in Europe to return to a nationwide lockdown, albeit one markedly less draconian than the measures put in place in the spring.
Public gatherings are banned, restaurants, bars and cinemas are once again closed and movement outside the home has been limited. But parks and schools are still open and a wider range of businesses are allowed to remain open.
The limits could start to be lifted next month.
The French authorities are considering allowing small businesses and shops to reopen in the run-up to Christmas. Catholic worshipers have also protested in recent days, demanding that the government relax a ban on religious services.
But officials said they would only loosen the rules if the trends remain encouraging. A government spokesman, Gabriel Attal, said at a news conference on Wednesday that while there might be an “adaptation” of the rules next month, the country was “far from” lifting the lockdown.
At the same time, officials sought to reassure the public, saying that while the road may be long and hard, the country was on the right path.
“Your efforts are starting to pay off, you must definitely not stop them,” Olivier Véran, the health minister, told the BFM TV news channel on Tuesday. “Yes it’s long, yes it’s difficult, but that’s the price to return to a normal life.”
In other news from around the world:
The “Sweden model” of very light restrictions has been the subject of fascination even as the effectiveness of the approach is still debated. But on Tuesday, King Carl XVI Gustaf captured a country dramatically shifting to deal with a sharp virus surge: “Hold on tight,” he said in a statement posted on Instagram. The government announced the strictest limitations on the country since the coronavirus first appeared and warned that there will be darker days ahead. While Sweden’s number of Covid-19 deaths still pales in comparison to those countries like Italy or Spain, it is more than 10 times higher than in Finland or Norway.
The Turkish government, facing growing public anger over its handling of the pandemic and accusations that it is hiding the true toll of the coronavirus as the number of deaths rise, announced that it would close classrooms and impose new restrictions on movement on the weekends as part of a raft of measures to slow the spread. Restaurants and cafes will only be allowed to serve takeout, and shopping malls will be forced to close at 8 p.m. Turkey has reported at least 11,700 deaths, with more than 420,000 cases of infection. Local officials and opposition politicians say the government is hiding the true death toll.
The state of South Australia will go into lockdown for six days to contain a growing outbreak. The cluster, which has been traced to a traveler quarantining in a hotel, has included 22 cases since Saturday. Starting at midnight on Wednesday, only one person per household will be able to go out each day to access essential services like groceries or medical services. Restaurants, cafes, pubs and retail stores will close, as will schools and universities. Outdoor sports and physical activities are banned, and masks will be mandatory. After the six-day lockdown, South Australia will face another eight days with fewer restrictions, details of which have not yet been announced.
Senator Charles E. Grassley, Republican of Iowa, 87, on Tuesday became the latest lawmaker to be affected by the virus, announcing that he had tested positive. His absence helped to temporarily derail the confirmation of President Trump’s nominee for the Federal Reserve Board and shattered Mr. Grassley’s pride and joy, the longest consecutive voting streak in Senate history.
His diagnosis came the day after Representative Don Young of Alaska, also 87, disclosed that he had been hospitalized over the weekend after what he described as a particularly brutal bout with Covid-19. The twin announcements from two men whose gender and age put them at peak vulnerability to being killed by the virus underscored the risks that lawmakers are operating under as Congress continues to meet.
The marble-and-stone petri dish that is Capitol Hill is a vivid microcosm of the national struggle to confront and contain the spread of the pandemic, with partisan bickering often thwarting already unevenly enforced health precautions. Having effectively declared themselves essential workers, the nation’s lawmakers — a group of older Americans whose jobs involve weekly flights, ample indoor contact and near-constant congregating in close quarters — are yet again struggling to adapt their legislative and ceremonial routines to stem the spread of the virus, even as it rages within their ranks.
As of Tuesday afternoon, both Senator Rick Scott, Republican of Florida, and Mr. Grassley were in quarantine as a result of possible exposure, marking the first time Mr. Grassley had missed a vote since 1993. In the House, Mr. Young — who noted on Monday that he was “alive, feeling better and on the road to recovery” after being discharged — is among four lawmakers who have revealed they contracted the virus in the past month.
More than 80 members of Congress have either tested positive, quarantined or come into contact with someone who had the virus, according to GovTrack.
On Tuesday, the absence of Mr. Grassley and Mr. Scott temporarily stalled the confirmation of Judy Shelton, Mr. Trump’s Fed nominee, after Republicans fell short of the support necessary to advance to a final vote.
“There’s this kind of macho, ‘Well, I’m not afraid of Covid’ thing going on,” said Senator Brian Schatz, Democrat of Hawaii, who has one of the longest congressional commutes and has instructed his entire staff to work remotely. “We have to run the government — that’s our obligation. Our obligation is not to show that we’re personally unafraid, because we have to pass legislation to address this crisis, and we’re no good to anybody if we’re sick or quarantining.”
The New York City comptroller’s office filed a lawsuit on Wednesday seeking to force Mayor Bill de Blasio’s administration to turn over documents that may disclose whether the city botched its response to a coronavirus pandemic that has killed more than 24,000 New Yorkers and devastated the city’s economy.
The office of the comptroller, Scott M. Stringer, issued a subpoena in June as part of its investigation, which Mr. Stringer said was an effort to understand how the city made the decision to initially keep public schools open, and why frontline workers did not have access to protective equipment.
But the city has yet to turn over records from key agencies such as the health department or the city’s public hospitals, the lawsuit said.
“The city’s refusal to timely and fully comply with the subpoena is impeding and frustrating the comptroller’s ability to complete the investigation, as well as the exercise of the comptroller’s investigative authority,” Mr. Stringer’s office wrote in the lawsuit, which was filed in State Supreme Court in Manhattan.
Mr. Stringer said at a news conference in front of City Hall on Wednesday that the city appears to be intentionally stonewalling the query, which asks for records from November 2019 through March 22, 2020.
“I really don’t know what they are hiding,” Mr. Stringer said. “But I’ve had enough.”
The comptroller’s office has received about 30,000 pages of documents from the Fire Department and the Office of Emergency Management, officials said. But the city said that other agency documents will not be available until April 2021, almost a year after the investigation began.
City Hall officials questioned Mr. Stringer’s motivations, noting that he is considered to be one of the leading candidates to replace Mr. de Blasio as mayor in next year’s election.
“Sounds like a politician running for mayor, not someone focused on the public health crisis at hand,” said Bill Neidhardt, the mayor’s press secretary.
BERLIN — Police broke up an organized protest by coronavirus deniers, vaccine skeptics and right-wing extremists in Berlin on Wednesday as lawmakers passed legislation meant to undergird the government’s efforts to contain the spread of the virus.
Police officers in riot gear used water cannons to disperse the crowd, which gathered near the Brandenburg Gate. The protesters were ordered to leave around noon because they refused to wear masks or keep social distance. Some protesters threw rocks, bottles and firecrackers at the police in response.
As many as 10,000 demonstrators descended on the city in an effort to stop lawmakers from passing a bill that they said would give the state and federal governments too much power to override basic constitutional rights in the fight against the pandemic.
While Chancellor Angela Merkel’s pandemic response has found broad acceptance, opponents have been demonstrating actively since the government instituted its first lockdown in the spring. The protest movement combines people who question the government’s response to the pandemic, those who deny the existence of the virus altogether and those who have long called for the overthrow of Ms. Merkel’s government.
Not far from the water cannons, inside the Reichstag, where lawmakers debated the bill, far-right lawmakers from the nationalist AfD party protested the proceedings by refusing to wear masks and by ignoring social distancing rules. Other AfD lawmakers could be seen mingling with the demonstrators outside.
Federal and city authorities decided on Tuesday that a protest in front of the Reichstag building would be prohibited because it could disrupt proceedings in Parliament. During a big protest in August, a small group of protesters managed to climb the stairs of the Reichstag, prompting a nationwide outcry.
Hours before New York State’s order limiting private gatherings took effect on Friday, effectively barring large holiday parties, an upstate sheriff said that he would not enforce it. His office, he said, would never interfere with “the great tradition of Thanksgiving dinner.”
Under an executive order, indoor and outdoor gatherings at private homes were limited to 10 people aside from residents. Gov. Andrew M. Cuomo said the rule was intended to target house parties, which the state’s contact tracers have found to be a significant source of new infections.
The state’s daily numbers of new coronavirus cases is climbing, threatening New York’s progress toward tamping down the spread of infection.
New York is not the only state to impose such a restriction leading up to Thanksgiving. New Jersey and Connecticut have issued similar rules; Michigan has banned indoor gatherings of more than two households; and Vermont and Washington State barred indoor gatherings outside of immediate households.
New York’s rule is in line with guidance from the Centers for Disease Control and Prevention, which says the safest way to have a Thanksgiving gathering is to keep it limited to one’s household.
Conservative local officials and sheriffs have so far issued the fiercest rebukes of Mr. Cuomo’s order, which was announced last week. Their open refusals to enforce the ban reflect a national pattern of conservative officials’ criticizing restrictions meant to keep the virus at bay, orders that opponents denounce as violations of civil liberties.
“It is unenforceable,” said Steve McLaughlin, a Republican who is the Rensselaer County executive and a frequent critic of Mr. Cuomo. The county’s sheriff has said he would not enforce the order. “And I believe it’s unconstitutional as does pretty much every sheriff I’ve spoken to.”
At a news conference on Wednesday, Mr. Cuomo blasted the sheriffs who said they were not planning to enforce his eecutive order.
“I don’t believe as a law enforcement officer, you have a right to pick and choose whta laws you will enforce,” he said.
He added: “It’s arrogant, and it violates your constitutional duty.”
The mayor of Boston — where roughly 140,000 students attend some 30 colleges and universities — said that if students planned to go home for the Thanksgiving holiday, they should not plan on returning anytime soon.
“If you go home for Thanksgiving, you should not be returning to Boston this semester,” Marty Walsh, the city’s mayor, wrote on Twitter on Tuesday.
His announcement added another wrinkle to what was already an agonizing and complicated choice facing students across the United States: go home and spend time with their family, possibly putting them at greater risk of contracting the coronavirus, or stay on campus and celebrate the holiday in a new way.
Schools like Boston University have been pleading with students to stick around for a “Friendsgiving” on campus. If students do leave, even if they do not travel outside the state, university officials said they would have to self-isolate for seven days when they return, and test negative three times befoe returning to class, according to BU Today.
“This means remaining in your room, attending courses remotely, and exiting the building only for medical appointments or meals,” Kenneth Elmore, the dean of students, wrote in an email to students, according to the university newspaper. “Violations of this advisory may result in disciplinary action up to and including suspension”
Eager to avoid the logistical nightmare of thousands of students migrating in and out because of the holiday, many universities around the country — including the University of Connecticut and New York’s SUNY campuses — have planned to end in-person classes before Thanksgiving and require students to finish the term remotely.
For colleges and universities that are encouraging students to return home until the spring semester, the measures they are taking to reduce the chances that those students might carry the coronavirus with them are a patchwork. Many are offering little more than optional testing and advice. Only a minority of schools are mandating that students test negative for the coronavirus before they leave campus.
New Orleans announced that there would be no parades during the February 2021 Mardi Gras celebrations, bowing to the near-certainty that the coronavirus pandemic will remain a public health crisis through the winter.
The crowds that typically line the city’s streets for weeks each February would have the potential to become superspreader events, running far afoul of the city’s current limit of 250 people at gatherings. The city has solicited ideas for how to safely celebrate under the current coronavirus restrictions, but the typically joyous, colorful affairs that attract seas of tourists will not go on as usual.
“We know that what we celebrate next year is not going to look like it’s looked in any other year,” Beau Tidwell, a city spokesman, said at a news conference on Tuesday.
City officials were careful to specify that Mardi Gras was not being canceled; there were still likely to be smaller events planned. But they would bear little resemblance to the enthusiastic bacchanals long associated with the city.
Dan Kelly, president of the Krewe of Endymion, a social club that organizes a parade, told nola.com that the restrictions came as “a total shock.”
Putting on the parades, he said, “means a lot to the city, and it means a lot to the people of New Orleans.”
Researchers in Denmark reported on Wednesday that surgical masks did not protect the wearers against infection with the coronavirus in a large randomized clinical trial. But the findings conflict with those from a number of other studies, experts said, and is not likely to alter public health recommendations in the United States.
The study, published in the Annals of Internal Medicine, did not contradict growing evidence that masks can prevent transmission of the virus from wearer to others. But the conclusion is at odds with the view that masks also protect the wearers — a position endorsed just last week by the Centers for Disease Control and Prevention.
Critics were quick to note the study’s limitations, among them that the design depended heavily on participants reporting their own test results and behavior, at a time when both mask-wearing and infection were rare in Denmark.
Coronavirus infections are soaring throughout the United States, and even officials who had resisted mask mandates are reversing course. Roughly 40 states have implemented mask requirements of some sort, according to a database maintained by The New York Times.
From early April to early June, researchers at the University of Copenhagen gave half their recruits surgical masks and said to wear them when leaving their homes; the others were told not to wear masks in public.
At that time, 2 percent of the Danish population was infected — a rate lower than that in many places in the United States and Europe today. Social distancing and frequent hand-washing were common, but masks were not.
The researchers had hoped that masks would cut the infection rate by half among wearers. Instead, 42 people in the mask group, or 1.8 percent, got infected, compared with 53 in the unmasked group, or 2.1 percent. The difference was not statistically significant.
“Our study gives an indication of how much you gain from wearing a mask,” said Dr. Henning Bundgaard, lead author of the study and a cardiologist at the University of Copenhagen. “Not a lot.”
Participants reported their own test results; mask use was not independently verified, and users may not have worn them correctly. Also, the incidence of infections in Denmark was lower than it is today in many places, meaning the effectiveness of masks for wearers may have been harder to detect, some experts noted.
The study’s conclusion flies in the face of other research suggesting that masks do protect the wearer. In its recent bulletin, the C.D.C. cited a dozen studies finding that even cloth masks may help shield those who wear them.
Susan Ellenberg, a biostatistician at the University of Pennsylvania Perelman School of Medicine, noted that protection conferred by masks on the wearer trended “in the direction of benefit” in the trial, even if the results were not statistically significant.
“Nothing in this study suggests to me that it is useless to wear a mask,” she said.
She wrote “I Will Always Love You” and “Jolene” on the same day and built a theme park around herself. She has given memorable onscreen performances as a wisecracking hairstylist and a harassed secretary. She even helped bring about the creation of “Buffy the Vampire Slayer.”
Now, Dolly Parton’s fans are crediting her with saving the world from the coronavirus. It’s an exaggerated, tongue-in-cheek claim, to be sure. But for legions of admirers, Ms. Parton’s donation this spring to Vanderbilt University Medical Center, which worked with the drugmaker Moderna to develop a coronavirus vaccine, was another example of how the singer’s generosity and philanthropy have made her one of the world’s most beloved artists.
In April, Ms. Parton announced that she had donated $1 million to Vanderbilt after her friend Dr. Naji Abumrad, a professor of surgery at the university, in Nashville, told her about the work researchers were doing to come up with a vaccine.
Her contribution, which became known as the Dolly Parton Covid-19 Research Fund, helped pay for the first part of the vaccine research, which was led by Dr. Mark Denison, a professor of pathology, microbiology and immunology at Vanderbilt. The federal government eventually invested $1 billion in the creation and testing of the vaccine, but Dr. Denison said it was Ms. Parton’s money that funded the “critical” early stages of the research.
“Her money helped us develop the test that we used to first show that the Moderna vaccine was giving people a good immune response that might protect them,” Dr. Denison said on Tuesday.
On Monday, after Moderna announced that early trials of the vaccine showed a 94.5 percent effectiveness rate, fans reacted rapturously.
“Shakespeare may have written King Lear during the plague, but Dolly Parton funded a Covid vaccine, dropped a Christmas album and a Christmas special,” the author Lyz Lenz said on Twitter.
The consequences of President Trump’s refusal to concede the election has leaders in government and business worried. Speaking at the DealBook Online Summit Tuesday and Wednesday, they said administrative delays threaten a smooth transition that’s especially critical in a pandemic and amid economic crisis. Massachusetts Senator Elizabeth Warren said she was “very worried about the transition process.”
“This is not a game,” Ms. Warren added. “People around the world, people who would do us harm, are watching what’s happening. They’re watching the delay in the transition.”
Jamie Dimon, the chief executive of JPMorgan Chase, expressed similar dismay: “We need a peaceful transition. We had an election. We have a new president. We should support that, whether you like the election outcome or not, you should support the democracy because it is based on a system of faith and trust. ”
Refusal to concede doesn’t present just abstract threats, experts said. There are practical considerations, like the fact that the General Services Administration has so far refused to acknowledge President-elect Joseph R. Biden Jr.’s win, which means the incoming administration has no access to offices, experts, funds and information it needs to manage the pandemic and to govern in January.
The nation’s top infectious disease expert, Dr. Anthony S. Fauci, noted during the summit that in 35 years he has dealt with six administrations through five transitions. “I can say that transitions are extremely important to the smooth continuity of what we are doing,” he said. “You want to have the continuity.”
Albert Bourla, the chief executive of Pfizer, similarly noted on Tuesday that working on a coronavirus vaccine approval and release during a transition is not “ideal,” adding, “It’s always better when there is clear accountability and leadership.” Pfizer on Wednesday said that it planned to seek emergency regulatory approval for its vaccine “within days”; preliminary data have shown the vaccine to be 95 percent effective.
President-elect Joseph R. Biden Jr. put new pressure Wednesday on the Trump administration to authorize a presidential transition, telling a group of workers that the head of the General Services Administration could act now to give him access to federal resources to help plan his coronavirus response.
“The law says that the General Services Administration has a person who recognizes who the winner is,” Mr. Biden said. “And then they have to have access to all the data and information that the government possesses.”
“And it doesn’t require that there be an absolute winner. It says the ‘apparent’ winner. The ‘apparent’ winner,” Mr. Biden said.
Mr. Biden asked the small group gathered on a video call, which included nurses and a firefighter, to describe their experiences dealing with the virus, and he pledged to mount a major new effort to combat the pandemic. “We’re all ready to go and do an awful lot of work right now,” Mr. Biden said.
But he said his ability to plan was restricted by the delayed transition caused by President Trump’s refusal to acknowledge his victory and the refusal of Emily W. Murphy, the G.S.A. administrator, to sign the paperwork that would grant Mr. Biden’s transition team access to funds, equipment and government data.
Mr. Biden said he did not “have any budget for any of this” until he was sworn in or until Mr. Trump conceded defeat and began a transition. But he noted that he planned to work with state and local leaders on mask mandates.
Mr. Biden also complained that Senate Republicans had not agreed to the stimulus spending passed by the House earlier this year. (Senate Republicans offered their own scaled-back stimulus plan that failed to reach the 60-vote threshold necessary to advance the bill.)
“I’m hoping that the reason why my friends on the other side have not stepped up to do something is because of their fear of retribution from the president,” Mr. Biden said. “And hopefully when he’s gone, they’ll be more willing to do what they know should be done — has to be done — in order to save the communities they live in.”
“This is like going to war,” Mr. Biden added about fighting the pandemic. “You need a commander in chief.”
Mr. Biden also noted that, while deprived of access to federal experts and data, he had been immersing himself in the details of the pandemic since the spring, saying that he had been getting regular briefings for months “from some of the leading docs in the country.”
The Biden transition did not provide names and precise job descriptions of the people with whom Mr. Biden spoke.