President Joe Biden also extended the federal mask mandate through March 18.
PHILADELPHIA (WPVI) -- New travel rules are now in effect in light of the omicron variant.
Before landing in the U.S., all international travelers are now required to test negative for COVID-19 within one day of their departing flight. Initially, travelers had three days to test negative.
"I think it's a wise move because I think we should do everything we can to protect ourselves," said John Novarina of Collegeville. "We should be as safe as possible."
President Joe Biden also extended the federal mask mandate through March 18, which required travelers to wear masks in airports, on planes and on public transportation.
"I think that's the new world we're living in," said Mark Manning of West Chester. "We're going to have to make compromises to the way we've done things."
"I have both vaccines and the booster. Wearing a mask, loaded up on hand sanitizer and I'm just gonna take as many precautions as I can," added Arun Terwilliger of Eugene, Oregon.
Philadelphia announced its first omicron case on Friday -- it's Pennsylvania's first.
Information is limited but health officials like Dr. Anthony Fauci have referred to early data as "encouraging."
Dr. Marci Drees, the Chief Infection Prevention Officer with ChristianaCare, said most patients in the US have exhibited mild symptoms.
"In South Africa, they've seen this very dramatic rise in cases but they haven't started to see a rise in hospitalizations or deaths. Now some of that may be a time lag so we may be at the mercy of time."
And as we head into the holidays, health professionals are emphasizing the delta variant is proving to be more dangerous. They are pushing everyone to get vaccinated to boost their immunity.
"What we don't know yet is if omicron can really outcompete delta," said Dr. Drees. "And we have so much delta right now, unfortunately, that's it's very much the dominant strain. Omicron may end up co-circulating or it may not be able to compete... we don't know yet."