Omicron variant 'almost definitely' in U.S. -Former FDA chief

"Just looking at the number of cases coming off planes this weekend," Gottlieb said, "it's almost a certainty that there have been cases that have gotten into the United States."

Gottlieb said while it's unknown whether the Omicron variant is able to evade vaccines, the United States is in a much better position now than it was a year ago to detect the new variant.