WILMINGTON, Del. — President-elect Joe Biden pledged to put Americans 65 and older near the front of the line for coronavirus vaccines and to expand the number of vaccination sites to quickly make up for the Trump administration's bungled response.

Biden vowed to use available supplies more efficiently and equitably to supercharge the effort to get shots into arms after Trump’s promise to vaccinate 20 million people before Jan. 1 fell far short.

“We’ll manage the hell out of this operation,” Biden said Friday, as he offered a sober assessment of the nation’s ability to conquer the pandemic.

Biden laid out his plan to speed up vaccinations by focusing on people who need them most at a time when covid-19 cases and hospitalizations have reached record levels.

Raising the urgency of the vaccine effort was a warning Friday from the Centers for Disease Control and Prevention that the highly contagious variant of the novel coronavirus first seen in Britain will become the dominant strain in the United States within about two months.

More than 23 million cases of covid-19, the illness caused by the coronavirus, have been reported nationwide as the country’s death toll approaches 400,000.

As of Friday, slightly more than 31 million vaccine doses have been distributed around the country, and at least 10.6 million people have been vaccinated, CDC figures show.

Biden repeated a warning that the pandemic will worsen and that more Americans will die in coming months before the vaccine can be administered to enough people to turn the tide.

“I’m convinced we can get it done, and this is a time to set big goals, to pursue them with courage and conviction, because the health of the nation is literally at stake,” Biden said.

Vaccines are one of the most critical aspects of the federal response to the coronavirus pandemic that continues to hobble the U.S. economy and keep children away from schools. Biden has pledged to administer 100 million doses in his first 100 days in office.

Biden also said Friday that he feels safe being inaugurated at the U.S. Capitol, where pro-Trump rioters overran police, ransacked the building and killed one officer on Jan. 6. Police fatally shot one woman and three other people died of causes described as medical during the melee.

Biden’s call for anyone 65 and older to get the vaccine goes beyond the current recommendations of the CDC, which had suggested that doses in the initial weeks of an unprecedented mass vaccination campaign be reserved for health-care workers and residents and staffers at nursing homes and other long-term-care facilities.

This week, however, Trump’s top health officials and leaders of Operation Warp Speed, the administration’s initiative to develop, manufacture and distribute coronavirus vaccines, suggested that vaccine access should be expanded to include people over 65.

The Trump administration also said shots should be available to Americans of any age who have significant medical conditions that put them at great risk for serious illness or death if they become infected with the virus.

Biden’s plan does not go that far. And even for the older Americans, his plan cautions that it “won’t mean that everyone in these groups will get vaccinated immediately, as supply is not where it needs to be. But it will mean that, as vaccines become available, they will reach more people who need them.”

And the plan says the incoming administration will look to an advisory committee that recommended vaccination priorities to the CDC to continue to hone its recommendation to make the vaccine program more equitable and effective.

Biden also pledged that on his first day in office he would direct the Federal Emergency Management Agency to set up new, federally administered vaccination sites.

“By the end of my first month,” he said, “we’ll have 100 of these centers,” including in school gyms, sports stadiums and community centers, as well as a fleet of mobile clinics.

Overall, the president-elect’s plan lays out a more muscular federal role than the Trump administration’s approach, which has relied heavily on each state to administer vaccines once the federal government ships them out. Many of the elements — such as seeking to expand the number of vaccination sites and setting up mobile vaccination clinics — were foreshadowed in a radio interview Biden gave last week and in an economic and health “relief plan” he issued Thursday, which contains a $20 billion request of Congress to pay for a stepped-up campaign of mass vaccination.

The plan also calls for greater reliance on pharmacies to dispense shots. The president-elect said his administration “will immediately start a new effort” in collaboration with independent and chain pharmacies, so that people can make appointments nearby and arrive knowing they can get vaccine shots. It was not immediately clear how that initiative might extend beyond the Trump administration’s recent announcement that it was accelerating a plan to distribute vaccines through retail pharmacies that could schedule appointments.

Biden’s plan envisions distributing a larger share of vaccines that have been manufactured so far to be used for the first dose in a two-shot regimen. The vaccine manufactured by Pfizer and the German biotech firm BioNTech calls for a second dose to be given 21 days later; the Moderna vaccine calls for a second dose 28 days later. Considerable disagreement has surrounded the question of how much vaccine should be held back to ensure that people can get their second shots on time.

Biden’s plan says that the “vast majority” will be distributed as soon as it has been manufactured and that a “small reserve” will be held back to compensate for unforeseen shortages or manufacturing delays.

Peter Hotez, a vaccine expert at Baylor College of Medicine, said that Biden’s plans to increase the administering of vaccines were good but that the incoming administration faces another problem: “supply.”

“We don’t have enough vaccine,” he said. “We are not going to be able to do it just with mRNA vaccines,” the technology used by Pfizer-BioNTech and Moderna, which have received emergency authorization from regulators. “We are going to have to accelerate the timetable for the other types of vaccines.”

Also Friday, Biden named David Kessler, a close adviser to him on the coronavirus crisis, to help lead the incoming administration’s efforts to accelerate the manufacturing, distribution and administering of coronavirus vaccines, the Biden transition team announced Friday morning.

Kessler, who was commissioner of the Food and Drug Administration under presidents George H.W. Bush and Bill Clinton, will take over the role played by Moncef Slaoui, who has been the chief scientific adviser to Operation Warp Speed, the Trump administration’s public-private initiative to hasten the manufacture and distribution of vaccines to curb the pandemic. Kessler’s new role was first reported by the New York Times.

Beginning last March during the presidential campaign, Kessler, a pediatrician and lawyer, briefed Biden on the pandemic several times a week.

Kessler is one of eight people the transition announced early Friday will work on the government’s coronavirus response in various capacities.

Among them, Andy Slavitt will become a senior adviser to Jeff Zients, the Biden White House’s coronavirus response coordinator. Slavitt was an acting administrator of the Centers for Medicare and Medicaid Services under President Barack Obama. Since then, he has formed a health think tank and advocacy organization and has been an outspoken critic of Trump-era health policies, especially regarding the Affordable Care Act.

Biden also announced that Francis Collins will continue in his role as director of the National Institutes of Health.

Goldstein and McGinley reported from Washington.