Promising news that Moderna's coronavirus vaccine is stunning 94.5% effective.

We have two vaccines that are really quite effective. So I think this is a really strong step forward

to where we want to be about getting control of this outbreak.

This week, Moderna announced positive preliminary results for its COVID-19 vaccine.

This comes just a week after Pfizer, released similar data suggesting their vaccine is more than 90% effective.

No matter how you look at it, this is good news. No doubt about it.

But it does raise the next logical question.

When a vaccine becomes available, who's going to get it first?

President Trump has said that states should prioritize frontline workers, the elderly, and high-risk Americans.

But if you do the math, those groups could easily add up to more than the number of doses that will be immediately available,

if one or even both of these vaccines are authorized.

On top of that, there is a complex distribution plan to be sorted out.

One major hurdle, for example, is that Pfizer's vaccine in particular must be kept at extremely cold temperatures until it's ready to be administered.

So low that not every health care facility has the proper equipment to store it.

Today, we'll look at the factors the government will have to weigh when determining where and to whom the vaccine will go first.

We're also going to examine the big question that must be answered about distributing the vaccine globally.

I'm Dr. Sanjay Gupta, CNN's Chief Medical Correspondent.

And this is coronavirus, fact versus fiction.

Well, you know, that issue divides in two ways.

One is, are we going to have supplies of vaccine that we share with the world?

And then the second part is, okay, if we kept them here at home, who's going first among Americans?

Art Kaplan is a professor of bioethics at the NYU Grossman School of Medicine.

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