That smooth handoff is in stark contrast to what is happening now as President-elect Joe Biden prepares to assume power during a double-barreled crisis involving a lethal virus and its economic fallout that experts say demands close cooperation. Instead, as the coronavirus overwhelms U.S. hospitals and kills more than 3,300 people a day on average, the Trump administration has balked at providing access to information and failed to consult with its successors, including about distributing the vaccines that offer the greatest hope of emerging from the pandemic.

For more than a month, the Biden team pressed to attend meetings that offered “real-time information on production and distribution of vaccine” — important details for the president-elect’s advisers debating ways to bring the pandemic under control, said a transition official, speaking on the condition of anonymity to discuss private interactions.

While health agencies’ career staff have been helpful, it was not until this week that Biden officials were allowed to attend meetings of Operation Warp Speed, the administration’s initiative to accelerate vaccine development and distribution. They were also not invited to the two Warp Speed sessions this weekend when Trump officials decided on sweeping changes to try to speed up the sluggish vaccine rollout. Nor were they briefed on those changes in advance.