The Centers for Disease Control and Prevention in the U.S. is monitoring 110 people located in 26 states for the coronavirus.

Thirty-two of those have tested negative for the virus, five have tested positive. Tests are pending for 73 cases, the CDC said Monday.

The five who tested positive recently traveled to China. U.S. health officials say there is no sign yet that the virus is spreading inside the U.S. to those who have not traveled to China. But that could change, according to officials.

“We understand that many people in the United States are worried about this virus and how it will affect Americans,” Dr. Nancy Messonnier, the director of the National Center for Immunization and Respiratory Diseases, said on a conference call with reporters Monday. “Every day we learn more. Every day we assess to see if our guidance or our response can be improved.”

The virus is novel, meaning it is new and medical scientists still have much to learn about it. It is not yet known how easily it can be transmitted between humans.

It has now been reported in 14 nations, including the U.S., said Messonnier.

“At this time, the virus is not spreading in our community,” Messonnier said. “For this reason we believe the immediate health risks from the virus to the general American public is low at this time.”