Epidemiological characteristics of imported respiratory infectious diseases in China,2014-2018

Background:With the progress of globalization,international mobility increases,greatly facilitating cross-border transmission of respiratory infectious diseases(RIDs).This study aimed to analyze the epidemiological characteristics and factors influencing imported RIDs,with the goal of providing evidence to support adoption of high-tech,intel-ligent methods to early find imported RIDs and prevent their spread in China.Methods:We obtained data of imported RIDs cases from 2014 to 2018 from the Inbound Sentinel Network of Customs and the National Notifiable Diseases Reporting System in China.We analyzed spatial,temporal,and population distribution characteristics of the imported RIDs.We developed an index to describe seasonality.Pearson correlation coefficients were used to examine associations between independent variables and imported cases.Data analyses and visualizations were conducted with R software.Results:From a total of 1409265253 inbound travelers,31732(2.25/100000)imported RIDs cases were reported.RIDs cases were imported from 142 countries and five continents.The incidence of imported RIDs was nearly 5 times higher in 2018(2.81/100000)than in 2014(0.58/100000).Among foreigners,incidence rates were higher among males(5.32/100000),0–14-year-olds(15.15/100000),and cases originating in Oceania(11.10/100000).The vast majority(90.3%)of imported RIDs were influenza,with seasonality consistent with annual seasonality of influenza.The spatial distribution of imported RIDs was different between Chinese citizens and foreigners.Increases in inbound travel volume and the number of influenza cases in source countries were associated with the number of imported RIDs.Conclusions:Our study documented importation of RIDs into China from 142 countries.Inbound travel poses a significant risks bringing important RIDs to China.It is urgent to strengthen surveillance at customs of inbound travelers and establish an intelligent surveillance and early warning system to prevent importation of RIDs to China for preventing further spread within China.