Bloomberg news rpeorts that the new US travel alert, Level 3, is the second-highest of four State Department advisories.
Previously, the US had urged citizens to “exercise increased caution” when visiting China, while avoiding any travel to the area near Wuhan, the city of 11 million where the epidemic started.
The US may also expand travel screening at its borders and is closely monitoring 110 people to stop the virus, testing them for presence of the pathogen. As of Monday morning, there have been no new U.S. cases after the first five patients were identified in the past week.
“At this time in the US, this virus is not spreading in the community,” said Nancy Messonnier, the Centers for Disease Control and Prevention’s director of the National Center for Immunization and Respiratory Diseases.
Anxiety is growing amid evidence that the disease has an incubation period of as long as two weeks before those infected start to show symptoms. That raises the possibility that people could travel and eventually infect others before realizing they have the illness. But Messonnier said that so far there has been no clear evidence that the virus can spread during the incubation period before patients have symptoms.
The new coronavirus appears to be less contagious than highly infectious viruses like the measles, she said. Coronaviruses like this one, so named because of their crown-like shape, are generally transmitted by respiratory droplets, she said.