And without shipping a single extra vial, no less. On one hand, you have to wonder how this got missed. On the other hand, don’t look a gift horse in the mouth:

Pharmacists have found a way to squeeze extra doses out of vials of Pfizer’s vaccine, potentially expanding the nation’s scarce supply by up to 40 percent.

The Food and Drug Administration said late Wednesday that those extra doses could be used, clearing up confusion that had caused some pharmacists to throw away leftover vaccine for fear of violating the rules the agency set last week.

“Given the public health emergency, FDA is advising that it is acceptable to use every full dose obtainable,” an agency spokesperson told POLITICO, mirroring language that a federal health official sent to state vaccine providers Wednesday morning.

The Washington Post followed up this morning, citing Politico’s report, by clarifying that it’s still not certain how many doses there are in the Pfizer vials. It depends in large part on how the vials are handled by providers, and what syringes get used. What does seem clear is that Pfizer underestimated its own capacity:

That means the supply of remaining vaccine could be up to 40 percent greater, though the drugmaker cautions that it’s uncertain how many extra doses are available. The FDA and Pfizer also caution that any leftover vaccine from different vials that is smaller than a full dose should not be mixed together , which experts say risks cross-contamination.

“The amount of vaccine remaining in the multidose vial after removal of 5 doses can vary, depending on the type of needles and syringes used,” Sharon Castillo, a spokeswoman for Pfizer, said in a statement.

At least this answers another potential question, which is whether providers were under-dosing people with the vaccine. Both Pfizer and the FDA seem convinced that’s not the case, which means we really do have extra capacity in the current shipments, and likely in the shipments to come. That is all sorts of good news, even while the Trump administration negotiates for even more of Pfizer’s output:

Officials “are engaged in active negotiations” with Pfizer to boost the U.S. supply, HHS Secretary Alex Azar told reporters Wednesday morning. He added that Pfizer has notified the federal government of “manufacturing challenges” but did not disclose further details or indicate whether that could impact future vaccine production. …

“The U.S. government has asked us for additional 100 million doses. And we are in a position to provide them, but we are working the time frame,” Bourla said on CNBC’s Squawk Box on Monday. “We can provide a lot of that in the third quarter [but] the US government wants it in the second quarter.”

The “challenges” cited by Azar appear to be just keeping up with demand. Pfizer says it’s not having any production issues other than capacity, which is apparently the sticking point in the talks at the moment. Perhaps the US could offer to fund expansion of Pfizer’s production capacity in exchange for the extra doses, essentially wrapping the company more into Operation Warp Speed, which would be a good deal for both sides. Right now, though, the details of the talks are still being kept pretty quiet.

And of course, the US might get tens of millions more doses from Moderna, whose vaccine gets its formal review today from the FDA’s expert panel. Will they get the emergency-use authorization over the next 48 hours, like Pfizer did last week? Come on, man:

The U.S. is on the cusp of a second vaccine for COVID-19, with independent federal advisers reviewing data Thursday from Moderna that suggests its two-dose vaccine is safe and 94% effective.

An endorsement from the panel paves the way for an official green light by federal regulators to begin distributing next week some 5.9 million Moderna doses to the nation’s front-line health care workers and nursing home residents.

The Moderna batch would be in addition to the 6.4 million doses provided by Pfizer-BioNTech that started to roll out this week after being the first to get emergency authorization.

At this point, the panel would have to demonstrate a good reason not to recommend an EUA. The need to get vaccines out is a much higher priority than propping up bureaucratic processes, especially since Moderna might have a real complaint if they get held to a higher standard than Pfizer did for its EUA.

The FDA expert panel review is being streamed live. You might need more caffeine if you decide to stick it out all the way through.