Public health experts are divided over whether the U.S. should add AstraZeneca's coronavirus vaccine to its arsenal, or let the rest of the world have it.

Why it matters: By the time the AstraZeneca vaccine is authorized for distribution, the U.S. may already have more than enough supply. Meanwhile, most of the world is still waiting for shots.

What we're watching: It will take another month or so for the AstraZeneca vaccine to be available for use in the U.S., following the company's announcement yesterday that the two-dose regimen was 79% effective at preventing symptomatic illness.

• “The gap between supply and demand is closing considerably, and I think by the time we get to May, that gap will be closed," NIAID Director Anthony Fauci said.
• "At most, you’ll get a small percentage of Americans vaccinated with AstraZeneca, and it won’t speed up vaccinations, because by May, supply will not be the constraint," said Ashish Jha, the dean of public health at Brown University.

The other side: Angela Rasmussen, a virologist with Georgetown's Center for Global Health Science and Security, said she thinks the AstraZeneca vaccine will be useful in rural parts of the country where cold storage is a challenge.

The big picture: Monday's announcement is good news for the rest of the world, which is relying heavily on the AstraZeneca vaccine.

• Previous clinical trial data has been messy, and confidence in the vaccine may have been eroded recently by unsubstantiated concerns that it causes blood clots.
• The higher-than-expected efficacy avoids a “two tiered system," Jha said, in which less developed countries would receive a mediocre vaccine.
• And a stamp of approval from the Food and Drug Administration could help rebuild global trust in the vaccine.

Worth noting: The National Institute of Allergy and Infectious Diseases issued a statement early Tuesday expressing concern that AstraZeneca "may have included outdated information" in its U.S. trial that "may have provided an incomplete view of the efficacy data."

Go deeper: Biden's next challenge: Vaccine diplomacy