CNN  — 

The high number of holiday travelers during the pandemic has the nation’s top infectious disease expert worried.

“I know everyone wants to get back to the time when Christmas was a situation where you could have many, many guests indoors, congregating, having fun together,” Dr. Anthony Fauci, the long-time director of the National Institute of Allergy and Infectious Diseases, told CNN’s Wolf Blitzer on Tuesday.

But, “the situation is different now,” he said.

The Transportation Security Administration is reporting record-high pandemic travel, and said that it screened more than 4 million air travelers between Friday and Monday.

If Americans disregard the dire situation already underway and travel for the holidays anyway, Fauci warned that it “could be a very difficult January.”

“As you might imagine, it’s quite concerning to me,” he said. “This type of travel is risky, particularly if people start congregating when they get to their destination in large crowds, in indoor settings. I’m afraid that if, in fact, we see this happen, we will have a surge that’s superimposed upon the difficult situation we are already in. So, it could be a very difficult January coming up if these things happen.”

Fauci said whenever he talks about being careful as the coronavirus pandemic rages across the country, he’s accused of wanting to “cancel Christmas.”

“I don’t want to do that,” he said. “I want people to be more careful. I want them to limit traveling to the extent possible.”

Fauci also urged Americans to get the vaccine – he received his first dose of Moderna’s Covid-19 vaccine Tuesday.

“I feel very confident about what we’re doing and that’s the reason why I strongly recommend to everybody and everyone that when the vaccine becomes available to them to get vaccinated,” he said. “That is how we’re going to pu