A healthcare worker prepares a dose of the Moderna Covid-19 vaccine at a McLeod Health mass vaccination site inside the Darlington Raceway in Darlington. Photographer: Micah Green/Bloomberg

In a long-awaited move to increase vaccine supply, the U.S. Food and Drug Administration revised Moderna Inc.’s vaccine authorization to allow the company to ship vials filled with up to 15 doses, compared with the existing 10-dose vials.

The new multi-dose vials will contain a maximum of 15 vaccine doses, with a range of 13 to 15 doses that can be extracted depending on the type of syringes and needles used, the agency said in a statement late Thursday.

The agency also changed labeling for existing Moderna vials to allow for providers to extract as many as 11 doses from the vials, up from 10.

The FDA moves should help Moderna alleviate a bottleneck in vial-filling plants, and accelerate the pace at which it can roll out vaccine doses in the U.S.

“Both of these revisions positively impact the supply of Moderna Covid-19 vaccine, which will help provide more vaccine doses to communities and allow shots to get into arms more quickly,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement.

Moderna said in a statement it expected the new up-to-15-dose vials to start being shipped in coming weeks. The company also said the agency is allowing vials to be keep at room temperature for 24 hours, once removed from the refrigerator for usage, up from 12 hours.