Reports of new vaccinations have started to increase again across the United States, after a week of declines brought on by severe weather.
The country administered an average of about 1.5 million newly reported doses a day in the seven-day period ending Thursday, according to federal data, a slight increase from a low point of 1.4 million doses a day through Tuesday.
The Centers for Disease Control and Prevention reported Thursday that nearly 68.3 million doses of vaccine had been administered across the country since the U.S. vaccination campaign began in December. Since Jan. 20, the C.D.C. has reported that more than 50 million shots have been administered across the country.
But even as the pace of vaccination rebounds, it remains well below the roughly 1.7 million doses the country was averaging each day before a powerful winter storm disrupted shipping nationwide last week and forced vaccination sites to close in parts of the South and Midwest.
The average number of daily doses administered across the country had been steadily increasing as the two federally authorized vaccine manufacturers, Pfizer and Moderna, became more efficient and expanded production for their two-dose vaccines.
While that acceleration had been expected well before President Biden assumed office, officials have been anxious to highlight every increase in shipments as evidence that the new administration is fiercely battling the pandemic. A third vaccine, from Johnson & Johnson, which is a one-dose vaccine, is expected to be authorized soon.
On Thursday, Mr. Biden watched two firefighters and a Safeway grocery store manager get vaccinated at an event in Washington, and used the moment to mark the nation’s progress toward goal — considered fairly unambitious by many many experts — he set before he took office: 100 million shots in his first 100 days.
“We’ve been laser-focused on the greatest operational challenge this country’s ever undertaken,’’ he said, taking a shot at his predecessor, Donald J. Trump. “We are going from a mess we inherited to moving in the right direction,’’ he said.
At one point, Mr. Biden suggested without specifics that in late April or May there may be more vaccines available than people willing to take them.
“We’re gong to hit a phase in this effort, maybe as late as April or May, when many predict, instead of long lines of people waiting to get a shot, we’ll face a very different scenario, we’ll have the vaccine waiting,” he said.
The president’s optimism about supply tracks with congressional testimony from vaccine manufacturer officials earlier in the week. Pfizer and Moderna executives testified at a congressional hearing that they would deliver a total of 400 million doses by the end of May, and a total of 600 million by the end of July. Johnson & Johnson has pledged 20 million doses by the end of March and 100 million doses by the end of June, if its shot is authorized.
But on Thursday, Mr. Biden repeated his warning that “this is not a victory lap” and said he could not predict when life might return to normal.
With plans to distribute more doses in the weeks ahead, states have moved to expand eligibility to additional high-risk groups. But unlike in the early days of the vaccine campaign, when many states limited doses to medical workers and nursing home residents, a complex patchwork of rules has emerged from state to state and even county to county.
People 65 and older are eligible for vaccines in most states, but a handful of states still limit vaccines to those who are at least 70 or 75. At least 45 states have also expanded their occupation-based vaccination programs to include some nonmedical workers, such as police officers or grocery store workers, though…