Low immunization coverage, coupled with the widespread infestation of Ae. aegypti in cities near endemic areas and frequent travel to and from endemic areas, have increased the risk for the occurrence of outbreaks of urban yellow fever.

• 低的免疫接种率、加上埃及伊蚊在靠近地方性流行区的城市的广泛侵扰以及人们旅行经常往返于本病地方性流行区，都增加了城市型黄热病爆发流行发生的危险。