A top medical adviser to President Donald Trump’s administration saId Sunday he's confident that the Food and Drug Administration will approve the coronavirus vaccine from pharmaceutical company Pfizer this week.

FDA officials will meet to review the Pfizer vaccine Thursday and it could be authorized almost immediately.

“Based on the data I know I expect the FDA to make a positive decision, but of course, it’s their decision,” said Moncef Slaoui, the chief adviser to Operation Warp Speed told CBS “Face the Nation.”

But White House coronavirus task force coordinator Deborah Birx warned Americans not to let their guard down even so.

Birx, speaking on NBC’s “Meet the Press,” noted that more than 100 million Americans suffered preexisting heath conditions that put them at high risk if they contract the virus. The vast majority of those won’t have access to the vaccine for months still.

“I want to be very frank with the American people,” Birx said. “The vaccine’s critical, but it’s not going to save us from this current surge. Only we can save us from this current surge, and we know precisely what to do.”