The US State Department raised its travel advisory for China to Level 4: Do Not Travel due to the Wuhan coronavirus outbreak -- it's highest level. The alert reads:

Do not travel to China due to novel coronavirus first identified in Wuhan, China. On January 30, the World Health Organization has determined the rapidly spreading outbreak constitutes a Public Health Emergency of International Concern. Travelers should be prepared for travel restrictions to be put into effect with little or no advance notice. Commercial carriers have reduced or suspended routes to and from China. Those currently in China should consider departing using commercial means. The Department of State has requested that all non-essential U.S. government personnel defer travel to China in light of the novel coronavirus. Last week, the State Department ordered the departure of all non-emergency US personnel and their family members from Wuhan. On Thursday, nearly 200 Americans landed at a California military base following their evacuation from the city