But while Biden’s approach to the virus — frank warnings about the pandemic, mask mandates on federal property — is a reversal from Trump’s policies, his administration’s distribution of vaccines so far looks little different from that of its predecessor. Before Biden was sworn in, vaccines already were being delivered at a pace to meet his goal of 100 million doses in his first 100 days as president.

The new administration has said they’ll order new doses, but will do so by exercising options in contracts negotiated by the previous administration, which thought it premature to do so. They say they’ll use the Defense Production Act, which Trump used repeatedly. Rather than a total overhaul, they have otherwise made course corrections and modest shifts.

Biden’s ability to sharply change direction is inherently limited. The sheer magnitude of the distribution efforts would make any major changes costly and risk backsliding, even if temporarily. Some aspects of the program don’t offer much wiggle room to begin with, while the trickiest parts are yet to come — and entirely on Biden’s shoulders.