Hours after President-elect Joseph R. Biden Jr. declared the coronavirus a top priority, the magnitude of his task became starkly clear on Sunday as the nation surpassed 10 million cases and sank deeper into the grip of what could become the worst chapter of the pandemic yet.
The rate of new cases is soaring, and for the first time is averaging more than 100,000 a day in the United States, which has reported more Covid-19 cases than any other country. An astonishing number — one in 441 Americans — have tested positive for the virus just in the last week.
With 29 states setting weekly case records, the virus is surging at a worrisome level in more than half the country. Nationwide, hospitalizations have nearly doubled since mid-September, and deaths are slowly increasing again, with few new interventions in place to stop the spiraling outbreak.
“We are in a terrifying place,” said Dr. Krutika Kuppalli, an assistant professor of medicine at the Medical University of South Carolina who studies pandemic response. “All I see is cases continuing to go up, unless we do something.”
The nation’s worsening Covid-19 outlook comes at an extremely difficult juncture: President Trump, who remains in control of the federal response to the outbreak for the next 73 days, is openly at odds with his own coronavirus advisers, and the country is heading into a cold winter when infections are only expected to spread faster as people spend more time indoors.
In a victory speech on Saturday night, Mr. Biden said he was quickly focusing his attention on the pandemic, including plans on Monday to announce a new task force of coronavirus advisers. But he faces a nation divided over mask rules and business shutdowns, even as experts say the situation may further deteriorate before the new administration takes over in late January.
At the White House, President Trump has largely shuttered the coronavirus task force, insisted without evidence that the nation is “rounding the corner” in the fight against the virus, and suggested that he might fire the nation’s top infectious disease expert, Dr. Anthony S. Fauci. In the days before and after Election Day, six White House aides and a top campaign adviser tested positive for the virus.
All of it comes as colder weather in much of the nation will force people indoors, where the virus is known to spread more readily; as college semesters end and students return home; and as gatherings for Thanksgiving, Christmas and other holidays threaten to sow new outbreaks.
“I see this as a very precarious moment,” said Dr. Ashish K. Jha, dean of the Brown University School of Public Health, who said that the Trump administration had “basically thrown in the towel” on trying to control the pandemic, while Mr. Biden and his team have nothing to wield but “moral power and social power” until Jan. 20.
“Without significant action,” he said, “the idea that we have another 100,000 deaths by Inauguration Day would be a conservative estimate.”
Experts pointed to a number of steps a yet-to-be-sworn-in President-elect Biden could take to help control the pandemic. The options range from making a behind-the-scenes push for governors to issue mask orders and for Congress to supply more money for coronavirus testing, all the way up to a national lockdown if cases are still spiraling after Mr. Biden takes office.
Mr. Biden has said he wants to “shut down the virus, not the country.” But as he also vows to do “whatever it takes” to control the pandemic, the millions of Americans who turned out to vote in record numbers last week remain deeply split on how best to go about it.
“I’m anticipating the next shutdown,” said Voizene Stewart, 53, of Detroit, who said he voted for Mr. Biden after losing both his mother and his 34-year-old son to the coronavirus. Though virus cases in the county that includes Detroit are below peak levels from this spring, they have been rising steadily, with nearly 500 infections a day reported on average over the last week.
Even though he has gone months without spending significant time with his remaining children and grandchildren, he said he hopes that the president-elect will once again restrict businesses and urge people to stay home. “We need to get back to that,” he said. “They opened too early.” He noted with concern that the grocery store across the street from his home, which used to be quiet, was once again bustling with people; many customers emerging from the store on Sunday were wearing masks.
Many other voters, including those who viewed Mr. Trump as a champion of the economy, remain far from persuaded.
“We’ve already suffered almost irreparable damage from closing things down,” said Dennis Rohr, a city commissioner in Mandan, N.D., who said he voted for Mr. Trump. Though case counts remain extremely high in Mandan and across North Dakota, Mr. Rohr, 77, feared that any type of shutdown would bring a new, even more dangerous slew of problems, including job losses and loneliness.
Nine months into the pandemic, the country is fading from exhaustion and impatience, but the virus is spreading more than ever before.
Unlike in the spring, when the virus devastated New York City and other places on the East and West Coasts, it is now spreading nearly everywhere, with infections rising in 46 states.
In Pennsylvania, the state that gave Mr. Biden the electoral votes he needed to clinch the presidency, more people are testing positive for the coronavirus than at any other time in the pandemic. In Wisconsin, another pivotal state, hospitalizations for the virus have skyrocketed 500 percent in the past two months.
Surges have hit communities of all types, with remote counties and urban centers alike seeing major spikes. In rural Norton County, Kan., which has lately had one of the country’s highest infection rates, every resident of a local nursing home has tested positive, as have hundreds of people in prison. In Cook County, Ill., which includes Chicago, more than 4,600 cases were announced on Saturday.
Though the country is conducting far more tests now than it was in the spring, the soaring case numbers now reflect accelerating spread of the virus, not simply wider testing.
Hospitalizations, which give a clear picture of how many people are seriously ill with the virus at any given time, grew by 63 percent over the past month, according to data collected by the Covid Tracking Project. More than 55,000 people are now hospitalized with the virus, approaching earlier peaks of more than 59,000 in April and July.
Treatment has vastly improved since the height of the spring outbreak, when more than 2,200 people were dying per day. Even so, deaths, which tend to lag a few weeks behind new infections, are now trending upward. The country has averaged about 900 deaths a day over the last week, compared with about 700 a month ago.
Mr. Biden is in line to inherit one of the most serious and complicated national crises that any incoming president in more than half a century has faced.
While other presidents have entered office during an economic slowdown, including President Obama and Mr. Biden as vice president in 2009, not since Harry Truman in the final months of World War II has a new president faced a situation as “complex and multiheaded” as the pandemic, said Bruce J. Schulman, a political historian at Boston University.
Mr. Biden has said controlling the pandemic is the necessary first step to bringing back jobs, and has said that on his first day in office, he would move rapidly to appoint a “national supply chain commander” and establish a “pandemic testing board,” similar to Franklin D. Roosevelt’s wartime production panel.
On Sunday, Mr. Biden’s campaign released a first glimpse of his plan for the pandemic, including a commitment to “listen to science.” Public health experts offered initial praise for his coronavirus task force, which is expected to include Dr. Vivek Murthy, a former surgeon general; Dr. David Kessler, a former commissioner of the Food and Drug Administration; and Dr. Marcella Nunez-Smith, a Yale University professor.
But Mr. Biden has also promised to unify the country and govern as an “American president,” and millions of Americans, including many who supported Mr. Trump, voted with priority on the economy.
Kathleen Skeins, a travel agent outside Detroit, used to be busy planning all-inclusive trips abroad for her clients. Now, she said, she is among the many business owners in America who are “barely starting to get back on their feet.”
“We’ve already had so many people that have lost their dreams in the first shutdown,” said Ms. Skeins, 51, who said she cast her first ballot in about 30 years last week, and voted for Mr. Trump. While she doesn’t take the virus lightly, she said, she remains firmly opposed to any restrictions that could hurt her business.
“The virus is never going to go away,” she said. “It’s just a part of our lives.”