Even with much of the world in desperate need of COVID-19 vaccines, health officials in the U.S. say millions of doses could soon expire and sending those shots overseas isn't so simple.

Transcript

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With fewer people getting vaccinated, the U.S. has found itself in a predicament. In many states, there are unused vaccines sitting on shelves that could soon expire. It's a problem that most of the world could scarcely imagine. And as NPR's Will Stone reports, there is pressure not to let those doses go to waste.

WILL STONE, BYLINE: While the U.S. is giving out cash and prizes to convince people to get a shot, much of the world is in desperate need of more doses. The situation is dire in Latin America, says Dr. Carissa Etienne with the Pan American Health Organization.

CARISSA ETIENNE: Please don't wait until you have surplus doses. You need to share out of what you have now.

STONE: The urgency isn't just because of the alarming global surge of the delta variant. It's also because many doses sitting in the U.S. could soon be scrapped.

ETIENNE: Some countries have reported that millions of undeployed doses might be expiring soon.

STONE: Just how many is hard to say. Tens of millions of doses are dispersed across the U.S. Some are reserved for second shots, and it's possible the spiking COVID cases will lead more Americans to get their first shot. Still, given the drop-off in demand, it's likely millions will soon be at risk of expiring.

JENNY OTTENHOFF: We're going to start seeing this.

STONE: Jenny Ottenhoff is with the ONE Campaign, a nonprofit that focuses on global health.

OTTENHOFF: And we should be moving those as quickly as possible, especially as we know that more doses are going to be coming into the U.S. in the coming months.

STONE: She says the U.S. is expected to have an enormous surplus of doses by the end of the year. Already, some states are on the verge of destroying tens or even hundreds of thousands. Some states want to send those abroad, but Dr. Marcus Plescia says, at the moment, they can't.

MARCUS PLESCIA: The guidance has been pretty clear that the federal government just doesn't see that as an option right now.

STONE: Plescia is with the Association of State and Territorial Health Officials, a group that represents the people who run state health departments.

PLESCIA: Most of us have come to realize, you know, once it's out in the states, and particularly if it's been distributed out to local communities, pulling it all back is, you know, it's kind of asking for some kind of error or a problem.

STONE: The Biden administration tells NPR it's looking into how states could, in theory, return doses already in their control, so they can be sent abroad. Prashant Yadav studies medical supply chains at the Center for Global Development. He says this is much harder than shipping out vaccines from stockpiles managed by the federal government.

PRASHANT YADAV: Bringing back doses that are currently sitting in a very decentralized location is logistically quite complex.

STONE: There also appear to be some legal hurdles. Govind Persad, a law professor at the University of Denver, says states do at least need permission to send doses to countries.

GOVIND PERSAD: It's not clear what the federal interest is in roadblocking states from doing it, as opposed to helping them do it.

STONE: Then, there are the contracts with vaccine makers. Those are not fully public, but there is some language prohibiting the U.S. from using it abroad. But the administration is already sharing other doses overseas, and Persad says there are ways to get around the liability concerns. After all, why would drugmakers want to sue?

PERSAD: Given that the basic sort of PR of the suit would be we would rather these vaccines be thrown out in America than used to protect people overseas.

STONE: Yes, it may be complex and costly to reclaim these orphan doses, but Persad says it's still worth trying.

PERSAD: If you get even, you know, a hundred vaccines that would help people instead of being wasted, that's something that's actually really important.

STONE: And he says we shouldn't lose sight of what those vials sitting on a shelf somewhere represent - human lives that could be saved.

Will Stone, NPR News. Transcript provided by NPR, Copyright NPR.