Importation of yellow fever into China: assessing travel patterns.

Rapid increase in trade and a growing air passenger market encourages high travel volume between the regions associated with increasing risks of such importations including China. Eleven Chinese workers infected during the 2016 yellow fever (YF) outbreak in Angola imported YF into China highlighting the potential for spread into Asia. Using outbound and inbound travel data, we assessed travel patterns from and to YF endemic countries in relation to China. Among YF endemic countries, Angola has the second highest number of travellers into China and also receives the second highest number of Chinese visitors. We estimated that China needs around half a million YF vaccine doses to cover their population travelling to YF endemic countries. The recent importation cases into China also unmasked the low YF vaccination coverage among Chinese travellers and workers to Angola, indicating the need to ensure better adherence to the International Health Regulations.