New York Gov. Andrew Cuomo said on Wednesday that vaccine providers in the state have found extra doses in vials from Moderna, the biotech company whose vaccine was authorized by the FDA on Friday.
"Some good news: Many Moderna vaccine vials hold an extra dose. Vaccinators can often get 11 doses, not just 10, per vial," Cuomo tweeted on Wednesday.
"That means there are more doses than anticipated in the state's existing supply," he added.
A letter from the New York Department of Health stated that those administering vaccines would be allowed to draw more than 10 doses from the vials if enough remained, though they are not allowed to mix remnants from different containers.
Moderna did not immediately respond to Business Insider's request for comment on the extra doses.
Cuomo also announced that 89,000 New Yorkers have received vaccine shots as of Wednesday. Of those, 22,000 doses went to residents and workers in 90 nursing homes across the state.
Cuomo's announcement followed similar news about Pfizer's vaccine. Though each Pfizer vial was supposed to contain five doses, pharmacists discovered last week that they could squeeze out six or seven.
At first, some pharmacists threw the extra doses away, not wanting to violate the Food and Drug Administration's emergency-use guidelines, which state there are five doses per vial.
But on December 16, the agency said those extra doses could be used, according to Politico.
"Given the public-health emergency, FDA is advising that it is acceptable to use every full dose obtainable," an agency spokesperson said.
If all of Pfizer's vials actually contain seven doses instead of five, and all of those doses can be used, that could expand the US's supply of that vaccine by up to 40%. But it's more likely that not every vial has two additional doses.
It's also not yet clear how many additional doses Moderna's vials hold added up. The FDA has not yet provided official guidance as to whether those doses should be used.
In an email, FDA spokesperson Stephanie Caccomo referred Business Insider to FDA Commissioner Stephen Hahn's Twitter account, which said on Saturday that the FDA "is allowing providers to use as many full doses as can be obtained from multidose vaccine vials – about 6 for Pfizer and about 10 for Moderna."
On Friday, following the FDA authorization of the Moderna vaccine, the US government said it expected 5.9 million doses to be shipped to states within a week. The government has so far purchased 200 million doses of Moderna's vaccine.
Aria Bendix contributed reporting.