31 – the day after the World Health Organizationdeclared a global health emergency. Foreign nationals were barred from entering the U.S.if they had visited China within the past two weeks.... Non-citizen relatives were also permitted to enter the U.S., an exemption made by the president to prevent the separation of families.... Some of those flights arrived within the past week from Beijing into major U.S. airports in Los Angeles, San Francisco, and New York....