Live all day coverage: Joe Biden and Kamala Harris sworn into office.

WASHINGTON (AP) — President-elect Joe Biden predicted he would take office amid a “dark winter,” and the outlook is only getting bleaker.

No matter his first acts in the White House, the raging coronavirus pandemic could take another 100,000 American lives in his first month as president after crossing the grim marker of 400,000 deaths this week. He inherits a country weary from 10 months of lockdowns and business closures, divided by attacks on public health professionals and tantalized by the promise of widespread vaccination that will take months to have much effect.

Yet at noon on Wednesday, the virus, and the nation’s response to it, will be Biden’s responsibility.

“We’re inheriting a huge mess here,” incoming White House Chief of Staff Ron Klain bluntly told CNN Sunday. “The virus is going to get worse before it gets better,” he warned. “The virus is the virus. What we can do is act to control it.”

The effort to “control” the outbreak will likely be the defining test for the new administration: Biden has pledged to bring competence to a crisis that has made the U.S. exceptional for the wrong reasons — the most confirmed infections and deaths in the world.

The president-elect has lined up an expansive team of scientific and supply chain experts to boost testing and vaccinations and aims to shake up how the federal government manages the pandemic. Incoming press secretary Jen Psaki announced last week that Biden would be “phasing out” the Trump administration’s structure and centralizing all COVID-19 response at the White House under Biden counselor and coordinator Jeff Zients.

Biden’s team has only grown more concerned about the scale of the challenges ahead as they’ve prepared to take over. But the biggest challenge, in their view, was years in the making by the Trump administration: declining confidence in government and institutions.

The new administration hopes to rebuild trust in government by setting clear goals — be it for vaccinations in arms or reopening schools — and asking the public to be invested in achieving them.

Biden, aides say, is set to adopt a more top-down approach toward managing the crisis, expanding testing and administering vaccines. Where President Donald Trump emphasized a decentralized approach that left it up to individual states and cities to sort out complicated logistics, the new administration plans to directly engage with them to boost vaccinations and testing.

Similarly, Biden will use his inaugural address to try to bridge a patchwork of state and municipal guidelines and encourage all Americans to wear face coverings. Within hours of taking office, Biden will issue a mask mandate for those on federal property and during interstate travel. Such action was eschewed by Trump, who at times spread misinformation about the virus and what was needed to stop it.

Biden also has set a goal of boosting the pace of COVID-19 vaccinations to administer 100 million shots in his first 100 days in office.

But perhaps even more than the mechanics of the response, Biden must rebuild trust in the nation’s health institutions and the credibility of the presidency to direct a national response to the crisis.

Trump has been a vocal skeptic of science, promoting unproven drugs like hydroxychloroquine and repeatedly asserting that the coronavirus would go away on its own. When Trump’s White House coronavirus task force released a step-by-step strategy to gradually reopen communities, Trump undercut that by going on Twitter and demanding that governors “liberate” their states.

Biden’s response to the pandemic must be “disciplined, realistic and methodical,” said Princeton history professor Julian Zelizer. “It’s a long game policy challenge. The politics must be grounded on science.”

“The chaos we have seen did not have to be,” he added. “Biden’s team understands this.”

Tevi Troy, a former senior U.S. health official, wrote in his book “Shall We Wake the President?” that presidents have an obligation to “present accurate and actionable information to the American people and do so in a way that does not induce panic in the populace.”

Only if Americans have clear information can the government “fully leverage the resources of every level of government, the power of every institution and the initiative of free citizens,” he wrote.

Biden’s 100-day goal of administering 100 million shots is realistic — the independent Institute for Health Metrics and Evaluation in Seattle recently estimated 141 million people will be vaccinated by May 1 — but public health experts say it’s going to take a lot more than that to pull the nation out of the pandemic.

For starters, even more shots would be better. More like 200 million or 300 million.

And increased vaccinations need to be coupled with better, more widespread testing and a functional system for tracing the contacts of those who are infected. In most areas of the country, contact tracing is still rudimentary. Testing and contact tracing are critical for quickly snuffing out local outbreaks before they become regional and statewide.

Biden also has to be mindful that many Americans have qualms about getting the vaccine, and that missteps at the top levels of the federal government will not build confidence.

Critically, much of the effort has to take place in minority and immigrant communities, since Black and Latino people have borne a disproportionate burden of disease in the pandemic, and there is a history of health disparities in both communities.

“A hundred million doses in 100 days I think it is doable,” said Michelle Cantu, who heads efforts on infectious disease and immunization at the National Association of County & City Health Officials. “Navigating what that means is going to take a lot of coordination.”

Biden has called for Congress to provide money for hiring 100,000 public health workers to bolster the frontline agencies that Cantu’s group represents.

The Trump administration shepherded the development of two highly successful vaccines, with more on the way, and has delivered more than 30 million doses to states, U.S. territories and some major cities. Less than 40% of doses delivered have been administered, and Biden has deemed that a failure.

The pace of vaccinations has been picking up recently to around 900,000 daily shots, but the American Hospital Association estimated that it would take more like 1.8 million a day to reach the goal of widespread or “herd” immunity by the summer.

Biden has talked of setting up mass vaccination sites and deploying mobile units to hard-to-reach locations. But that remains aspirational.

“What you need to do is set up something that currently does not exist: a public health infrastructure that is geared to mass vaccinations,” said Dr. Paul Offit, director of a vaccine education center at the Children’s Hospital of Philadelphia. “This has to be people lining up in large facilities. You have to have thousands and thousands of people through.”

Although the challenges are daunting, there is a fundamental difference between the Trump White House and the incoming leadership that could give the Biden team an edge: A president who has pledged to follow the science.

Biden has designated Dr. Anthony Fauci, the government’s top infectious disease expert, to be his medical adviser. Fauci was under constant pressure under Trump, although he did not mince words in his public warnings. Trump publicly belittled his own director of the Centers for Disease Control and Prevention, and his Food and Drug Administration chief repeatedly came under threat of being fired because the president was impatient with the meticulous scrutiny that agency scientists were giving vaccines.

“At least (Biden) has surrounded himself with excellent people and he’s doing it on the basis of science,” said Offit. “He’s not going to attack all the science-based agencies, he’s going to embrace them in the belief that we will get better and better with each passing day.”