President-elect Joe Biden on Tuesday pledged to “change the course” of the coronavirus pandemic as he introduced key members of his health team at an event in Wilmington, Del. As he continues to build his administration, Biden has said he will announce his nominations for two other marquee jobs — including attorney general — by the end of the week. Meanwhile, according to people familiar with the transition plans, Biden is expected to name former agriculture secretary Tom Vilsack for the position again, and pick Rep. Marcia L. Fudge (D-Ohio) to head the Department of Housing and Urban Development.

President Trump, who continues to insist he won the election, appeared at a White House “vaccine summit” to tout his administration’s efforts to combat the pandemic. He also expressed hope that he would have a second term.

Here’s what to know:

  • Biden plans to tap retired Gen. Lloyd J. Austin III to be defense secretary, according to three officials familiar with the decision. If confirmed, Austin would be the first Black Pentagon chief.
  • Sen. Patrick J. Toomey (R-Pa.) is denouncing Trump’s efforts to have the Pennsylvania legislature overturn his election loss, calling the president’s actions “completely unacceptable.” Trump called the speaker of the Pennsylvania House of Representatives twice during the past week to make the extraordinary request.
  • Tuesday is “safe harbor” day. Under federal law, every state is expected to have made its election results official by the end of the day, setting up Biden for an electoral college victory next week.
  • Rep. James E. Clyburn (D-S.C.), chairman of the Biden inaugural committee, said that many of the Jan. 20 inauguration activities will be virtual because of the pandemic but that he hopes a more complete celebration can occur on the Fourth of July.