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.