Biden laid out three COVID-19 priorities for his first 100 days in office: a call for all Americans to voluntarily mask up during those 100 days, a commitment to administer 100 million vaccines and a pledge to try to reopen a majority of the nation’s schools.

“I know that out of our collective pain, we will find our collective purpose: to control the pandemic, to save lives, and to heal as a nation,” Biden said.

The president-elect also said he would use the power of the federal government to require people to wear masks in federal buildings and when traveling from state to state on planes, trains and buses.

Mostly that would codify policies already in place. But Biden said he would urge governors and mayors to impose similar requirements.

Topping the roster of Biden’s picks was health secretary nominee Xavier Becerra, a Latino politician who rose from humble beginnings to serve in Congress and as California’s attorney general. Others include a businessman renowned for his crisis management skills and a quartet of medical doctors, among them Anthony Fauci, the government’s top infectious-disease specialist.

The usual feel-good affirmations that accompany such unveilings were overshadowed by urgency, with new cases of COVID-19 averaging more than 200,000 a day and deaths averaging above 2,200 daily as the nation struggles with uncontrolled spread.

Vaccines are expected soon. Scientific advisers to the government meet Thursday to make a recommendation on the first one, a Pfizer shot already being administered in the United Kingdom. Indeed, President Donald Trump held his own event Tuesday, to take credit for his administration’s work to speed vaccine development.

But having an approved vaccine is one thing, and getting it into the arms of 330 million Americans something else altogether. Biden will be judged on how well his administration carries out the gargantuan task.

On Tuesday, the president-elect warned that his team’s preliminary review of Trump administration plans for vaccinations has found shortcomings. And he called on Congress to pass legislation to finance administration of vaccines as they become more widely available next year. That would effectively close the loop, from lab to patient.

The rest of Biden’s extensive health care agenda, from expanding insurance coverage to negotiating prices for prescription drugs, will likely hinge on how his administration performs in this first test of competence and credibility.

Becerra, Biden’s pick to head the Department of Health and Human Services, will be backed in the White House by businessman Jeff Zients, who will assume the role of coronavirus response coordinator. Running complex, high-risk operations is his specialty.

Alongside Fauci, the other medical doctors selected include infectious-disease specialist Rochelle Walensky to run the Centers for Disease Control and Prevention, Vivek Murthy as surgeon general and Yale epidemiologist Marcella Nunez-Smith to head a working group to ensure fair and equitable distribution of vaccines and treatments.

Participating by video, Fauci called Biden’s 100-day plan “bold but doable, and essential to help the public avoid unnecessary risks and help us save lives.”

Ever the straight talker, he admonished: “The road ahead will not be easy. We have got a lot of hard and demanding work ahead.”

HHS is a $1 trillion-plus agency with 80,000 employees and a portfolio that includes drugs and vaccines, leading-edge medical research and health insurance programs covering more than 130 million Americans.

In choosing Becerra to be his health secretary, Biden tapped a prominent defender of the Affordable Care Act. But Becerra, 62, will face questions in his Senate confirmation about whether he possesses sufficient health care and management experience.

Becerra as a congressman played an insider role helping steer “Obamacare” to passage, and as California attorney general he leads a coalition of Democratic states trying to block the Trump administration’s latest attempt to overturn it. He has been less involved in the day-to-day work of combating the coronavirus.

Becerra would be the first Latino to serve as U.S. health secretary. In announcing his pick Tuesday, Biden initially stumbled on the Spanish pronunciation of Becerra’s name.

But Biden was drawn to Becerra’s working-class roots, his longtime effort to increase access to health care and his willingness to work with Republicans to solve problems like getting patients access to COVID-19 treatments.

Accepting his nomination via video link, Becerra called it a “breathtaking opportunity” to help shape the future of health care.

“I share the president-elect and vice-president-elect’s determination to rebuild unity and civility in America,” he added.

Biden is under pressure from fellow Democrats to ensure that his Cabinet is diverse.

Then-California Gov. Jerry Brown appointed Becerra as California’s top prosecutor in late 2016. Becerra instantly struck a combative tone toward the incoming Trump administration.

Defending California’s implementation of the Affordable Care Act was a key priority, but he also focused on protecting young immigrants from deportation and defending California’s climate change laws.

As HHS secretary, Becerra would be responsible for overseeing the Office of Refugee Resettlement, which cares for unaccompanied minors who enter the U.S. illegally. Becerra has helped lead a coalition of fellow state attorneys general who sued over the Trump administration’s child separation policies.

Republicans immediately made clear their attack lines. Sen. John Cornyn of Texas argued that Becerra was unqualified because he lacked ties to the health care or pharmaceutical industries. Sen. Mike Braun of Indiana blasted his support for “Medicare for All,” which is not Biden’s policy. Abortion opponents have called Becerra “unacceptable.”

The HHS secretary’s job requires political connections, communications skills, managerial savvy, a willingness to learn about complex medical issues and a creative legal mind to use vast regulatory powers without winding up on the losing end of lawsuits.

Becerra will need to establish ties with governors who will play outsize roles in distributing the coronavirus vaccine.