As Moderna looks to increase the doses in vaccine vials, the White House announces an expected boost in manufacturing.

The upstart drugmaker Moderna is asking U.S. regulators to allow it to increase the amount of coronavirus vaccine put into each vial by as much as 50 percent, arguing that it can speed vaccines to patients by clearing away a simple manufacturing bottleneck: Getting medicine into bottles.

The Food and Drug Administration could decide within a few weeks how much more vaccine Moderna, the developer of one of the two federally authorized Covid-19 vaccines, can put into its vials. Moderna says it can raise the number of doses per vial from 10 to as much as 15.

The company has already been ramping up production of its vaccine, only to find a bottleneck in the bottling, capping and labeling process. With F.D.A. approval, more doses could start going into each bottle quickly, a welcome boost to the campaign to curb a pandemic that has killed more than 440,000 people in the United States alone. In a statement late Monday, Ray Jordan, a Moderna spokesman, said the constraint on dosage per vial was limiting Moderna’s output.

The Moderna proposal is part of a broader push by the Biden administration to speed vaccine distribution, including by clearing away obstacles in the “fill and finish” phase of manufacturing. Although the nuts-and-bolts stage receives less attention than vaccine development, it has been identified for years as a constraint on vaccine production.

On Tuesday, Jeffrey D. Zients, the White House’s Covid-19 response coordinator, said that the federal government would allocate a minimum of 10.5 million doses of coronavirus vaccines to states for the next three weeks, a bump of five percent resulting from an expected increase in manufacturing.

At a White House news conference, Mr. Zients framed the increase in doses as an accomplishment of the Biden administration, saying that “we have increased supply by more than 20 percent since we took office.” But the uptick in production has long been expected as the companies that make two federally-authorized vaccines, one from Pfizer and BioNTech and the other from Moderna, have scaled up their efforts. Last week, the companies increased their supply to the U.S. by 16 percent.

Governors were informed of the increase on a call Tuesday morning so that they would have more time to plan for vaccinations, Mr. Zients said, with at three weeks of notice for new allocation numbers — a cornerstone of a new effort by the Biden administration to improve a distribution system mired in uncertainty and confusion over limited supply and unused doses.

“That allows them to plan accordingly and know what staffing to have,” he said. “I think historically, there had been fluctuation. We are very attuned into not having that fluctuation.”

Moderna has discussed the possible change of the number of doses in vials with the F.D.A. but has not yet submitted manufacturing data to support it, people familiar with the discussions said. Federal regulators may be receptive to the idea of more doses in each vial, but could balk at the notion of a 50 percent increase.

The industry standard has long been 10 doses per vial, and federal regulators may be concerned that the extra punctures by needles of the rubber covering of the vial and the time required to extract more doses could increase the risk of contaminating the vaccine with bacteria.

At some point, too much liquid can cause a vial to break. Moderna has tested what happens when it adds additional doses, and determined that the limit is 15 doses, according to people familiar with the company’s operations who were not authorized to speak publicly. Moderna’s proposal to the F.D.A. for the dose increase was first reported by CNBC.

Packing more vaccine into each Moderna vial is one of a number of options White House and health officials are exploring as they push to expand production before the spring, when officials are expecting a renewed surge of infections from emerging variants of the virus. Some proposals have already been considered and dismissed, including a suggestion to combine fractions of doses left over in vials.

The maker of the other federally approved vaccine, Pfizer, is unable to increase the amount of vaccine in its vials because its manufacturing is geared toward a particular size of vial that can hold only about six doses. But Moderna’s vial is big enough to hold more than the 10 doses now allowed.

Asked about Moderna’s proposal, a White House spokesman on Monday said that “all options are on the table.”

Prashant Yadav, who studies health care supply chains with the Center for Global Development in Washington, said Moderna might be able to “relatively quickly” make more of its vaccine if it received the green light to add doses to each vial.

But he said it would not be an instant change. “I don’t think Moderna has a surplus sitting around,” he said.

Mr. Yadav said the finish-and-fill process is intensely automated, devoted to warding off contamination and precise to the microgram. At top speed, as many as 1,000 vials of vaccine can be filled per minute, he said.

He said a 15-dose vial carries a trade-off: It could lead to more wasted doses if the health care professional runs out of people to get inoculated and has to throw out the rest of the doses. But in the midst of a raging pandemic, experts said, that may well be a risk that federal health officials would be willing to take.