Major airports across the country are on high alert and screening some passengers for symptoms of a deadly new virus.
In San Francisco, those screenings are already underway.
Los Angeles and New York airports also have screenings planned.
The three cities have direct or connecting flights from Wuhan, China, which is believed to be the center of the outbreak.
Health workers will spend the coming weeks scanning passengers for fevers and flu-like symptoms to prevent a possible spread of the new virus.
On Saturday, passengers flying into San Francisco from Wuhan were screened, with some saying the process took a few hours.
"I think they did a good job. I think it's necessary because this is a big thing, this is about our health. So even if the process is like really long, I feel tired right now, but it's okay for me and I’m glad they do that,” said Qi Zhou, screened passenger from Wuhan.
The CDC says they are deploying around 100 additional staff to the three airports to assist with screenings.
The coronavirus is in the same family as the deadly severe acute respiratory syndrome, sars, and the middle east respiratory syndrome, mers.