title: Predicting the international spread of Middle East respiratory syndrome (MERS).
abstract: The Middle East respiratory syndrome (MERS) associated coronavirus has been imported via travelers into multiple countries around the world. In order to support risk assessment practice, the present study aimed to devise a novel statistical model to quantify the country-level risk of experiencing an importation of MERS case.
  
  
  
  We analyzed the arrival time of each reported MERS importation around the world, i.e., the date on which imported cases entered a specific country, which was modeled as a dependent variable in our analysis. We also used openly accessible data including the airline transportation network to parameterize a hazard-based risk prediction model. The hazard was assumed to follow an inverse function of the effective distance (i.e., the minimum effective length of a path from origin to destination), which was calculated from the airline transportation data, from Saudi Arabia to each country. Both country-specific religion and the incidence data of MERS in Saudi Arabia were used to improve our model prediction.
  
  
  
  Our estimates of the risk of MERS importation appeared to be right skewed, which facilitated the visual identification of countries at highest risk of MERS importations in the right tail of the distribution. The simplest model that relied solely on the effective distance yielded the best predictive performance (Area under the curve (AUC) = 0.943) with 100 % sensitivity and 79.6 % specificity. Out of the 30 countries estimated to be at highest risk of MERS case importation, 17 countries (56.7 %) have already reported at least one importation of MERS. Although model fit measured by Akaike Information Criterion (AIC) was improved by including country-specific religion (i.e. Muslim majority country), the predictive performance as measured by AUC was not improved after accounting for this covariate.
  
  
  
  Our relatively simple statistical model based on the effective distance derived from the airline transportation network data was found to help predicting the risk of importing MERS at the country level. The successful application of the effective distance model to predict MERS importations, particularly when computationally intensive large-scale transmission models may not be immediately applicable could have been benefited from the particularly low transmissibility of the MERS coronavirus.
authors.affiliation: Bolyai Institute, University of Szeged, Aradi vértanúk tere 1, Szeged, H-6720, Hungary.|Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 1130033, Japan.|Graduate School of Medicine, Hokkaido University, Kita 15 Jo Nishi 7 Chome, Kita-ku, Sapporo-shi, Hokkaido, 060-8638, Japan.
authors.forename: Kyeongah
authors.initials: K
authors.lastname: Nah
authors.affiliation: Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 1130033, Japan.|CREST, Japan Science and Technology Agency, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan.
authors.forename: Shiori
authors.initials: S
authors.lastname: Otsuki
authors.affiliation: School of Public Health, Georgia State University, Atlanta, Georgia, USA.|Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Chowell
authors.affiliation: Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 1130033, Japan. nishiurah@m.u-tokyo.ac.jp.|CREST, Japan Science and Technology Agency, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan. nishiurah@m.u-tokyo.ac.jp.|Graduate School of Medicine, Hokkaido University, Kita 15 Jo Nishi 7 Chome, Kita-ku, Sapporo-shi, Hokkaido, 060-8638, Japan. nishiurah@m.u-tokyo.ac.jp.
authors.forename: Hiroshi
authors.identifier: 0000-0003-0941-8537
authors.initials: H
authors.lastname: Nishiura
mesh_terms: D000401:Aircraft; D018352:Coronavirus Infections / Q000453:epidemiology / Q000635:transmission*; D014943:Global Health; D006801:Humans; D015994:Incidence; D065207:Middle East Respiratory Syndrome Coronavirus; D015233:Models, Statistical; D018570:Risk Assessment; D012529:Saudi Arabia / Q000453:epidemiology; D014195:Travel
keywords: Airline transportation network; Importation; Infectious disease; Middle East respiratory syndrome; Risk assessment