Joe Biden promised he’d bring in a competent, tested team to run the pandemic response, set ambitious vaccination targets and impose strict public health guidelines.

His team arrived at the White House with a 200-page response plan ready to roll out. But instead, they have spent much of the last week trying to wrap their hands around the mushrooming crisis — a process officials acknowledge has been humbling, and triggered a concerted effort to temper expectations about how quickly they might get the nation back to normal.

After a week on the job, Biden’s team is still trying to locate upwards of 20 million vaccine doses that have been sent to states — a mystery that has hampered plans to speed up the national vaccination effort. They’re searching for new ways to boost production of a vaccine stockpile that they’ve discovered is mostly empty. And they’re nervously eyeing a series of new Covid-19 strains that threaten to derail the response.

“It’s the Mike Tyson quote: ‘Everybody’s got a plan until they get punched in the mouth,’” said one person with knowledge of the vaccine effort who’s not authorized to discuss the work. “They are planning. They are competent. It’s just the weight of everything when you sit down in that chair. It’s heavy.”

Biden officials leading the coronavirus response launched a series of regular briefings this week to keep the public informed on the state of the pandemic and government efforts to contain it and rush vaccines out to as many Americans as possible.

But the briefings were short on details. And behind the scenes, officials say, the team was still struggling to get a handle on basic information, liaise with the career government workers who have been running the response and build out a long-term strategy for bringing — and then keeping — the virus under control.

“One of the virtues of a well-run transition is that by the time you take the reins, you have developed some rapport and trust with the career people you’re working with,” the person familiar with the administration’s work said. The “courtship has been unnaturally short,” the person added.

Nobody had a complete picture,” said Julie Morita, a member of the Biden transition team and executive vice president at the Robert Wood Johnson Foundation. “The plans that were being made were being made with the assumption that more information would be available and be revealed once they got into the White House.”

It’s a steep challenge that Biden officials said they’d been anticipating for weeks, amid a rocky transition period that left them scrambling to piece together vaccine distribution plans and coordinate with state health officials.

Yet in the days since taking over, the Covid response team has confronted a situation that officials described as far worse than expected — and that has prompted public assessments so dour they surprised some who had worked on the administration’s former transition team.

On Tuesday, Biden warned that the “vaccine program is in worse shape than we anticipated or expected,” echoing complaints from his chief of staff, Ron Klain, that a “plan didn’t really exist.”

Biden’s Covid response team has since made a concerted effort not to heap blame on the Trump administration, one official said — even as their vague allusions to a worse-than-expected situation have prompted speculation about what specific problems they’ve encountered.

But people with knowledge of the response detailed fresh concerns that are centered largely on the federal government’s vaccine supply. Biden’s team is still trying to get a firm grasp on the whereabouts of more than 20 million doses of Covid-19 vaccine that the federal government bought and distributed to states but has yet to record as being administered to patients.

Only a small percentage of those unaccounted for doses — roughly 2 million, two officials said — is due to lags in data reporting, the Biden team believes. That would mean the rest of the crucial supply is boxed away in warehouses, sitting idle in freezers or floating elsewhere in the complex distribution pipeline that runs from the administration to individual states.

That’s a dilemma that predated the Biden team’s arrival, with Biden himself hammering the vaccine rollout’s first weeks under the Trump administration as a “dismal failure.”

Yet the response team underestimated at the outset how difficult it would be to fix.

The Biden transition had only received high-level briefings on the distribution effort in the runup to the inauguration on Jan. 20, a transition official said, and was largely kept out of detailed discussions about the on-the-ground operation. The team didn’t get granular access to Tiberius — the central government system used for tracking vaccine distribution — until the transition’s final days.

It was not until after Biden was sworn in that the Covid response team discovered the system was blinded to much of the route that vaccines traveled from the government’s distribution hubs to people’s arms.