(Washington) US scientist Anthony Fauci, the White House adviser on the health crisis, warned Sunday that the Omicron variant of COVID-19 has been “outbreaking” around the world, raising concern about how many Americans remain unvaccinated.

“This virus is extraordinary,” Fauci said on CNN, referring to its rapid spread. “He will have the upper hand,” and “We will go through difficult weeks or months as winter approaches.”

He added on ABC, “It’s spreading really fast, quite literally, all over the world and without a doubt in our country.”

“When you have that level of vulnerability and you have a virus like Omicron that spreads very quickly, it is very likely that in some parts of the country we will see a huge strain on the hospital system as well as on hospital staff. Health is running out because of all of this,” he said, urging Americans to get vaccinated. And get a booster dose.

He insisted that the virus was “spreading all over the world, really.”

The Omicron variant is spreading at full speed around the world, causing restrictions in many countries such as the containment in the Netherlands.

The epidemic has claimed more than 5 million lives worldwide since the World Health Organization office in China reported the outbreak in late December 2019. The United States is the country with more than 800,000 deaths.