When the U.S. finally approves a vaccine, it will be because science says it's safe and effective.

That's what U.S. Food and Drug Administration Commissioner Stephen Hahn told a Senate committee on Wednesday.

Decisions to authorize or approve any such vaccine or therapeutic will be made by the dedicated career staff at FDA

through our thorough review processes and science will guide our decisions.

FDA will not permit any pressure from anyone to change that.

He said that before. What's new this week is that the FDA is reportedly working on updating its guidelines for vaccine evaluation, looking to make them more strict.

And while Hahn said only the FDA would green light a vaccine, here's what the president said about those new guidelines.

We're looking at that. That has to be approved by the White House. We may or may not approve it.

That sounds like a political move because when you have Pfizer, Johnson and Johnson, Moderna, these great companies coming up with these vaccines and they've done testing and everything else, I'm saying why would they have to be adding great length to the process?

That's President Trump suggesting his own administration's FDA may slow down vaccine development because of politics.

It's the latest example of the president's second guessing, even undercutting federal public health experts.

As for that guidance being considered by the FDA, reportedly it would require vaccine makers to follow patients for two months after receiving their second dose of a vaccine.

And that would give regulators more confidence in a vaccine's effectiveness and safety. It would also make it even less likely that a vaccine would be available even for limited emergency use before election day.

We're going to take a look at it and ultimately the White House has to approve it. And maybe we will, maybe we won't be able to take it over.

Consider this. Winter is coming and with coronavirus cases surging around the world, the US isn't the only country desperate for a vaccine.

From NPR, I'm Audie Cornish. It's Thursday, September 24.

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