The effect of travel restrictions on the spread of the 2019 novel coronavirus (2019-nCoV) outbreak


Motivated by the rapid spread of a novel coronavirus (2019-nCoV) in Mainland China, we use a global metapopulation disease transmission model to project the impact of both domestic and international travel limitations on the national and international spread of the epidemic. The model is calibrated on the evidence of internationally imported cases before the implementation of the travel quarantine of Wuhan. By assuming a generation time of 7.5 days, the reproduction number is estimated to be 2.4 [90% CI 2.2-2.6]. The median estimate for number of cases before the travel ban implementation on January 23, 2020 is 58,956 [90% CI 40,759 - 87,471] in Wuhan and 3,491 [90% CI 1,924 - 7,360] in other locations in Mainland China. The model shows that as of January 23, most Chinese cities had already received a considerable number of infected cases, and the travel quarantine delays the overall epidemic progression by only 3 to 5 days. The travel quarantine has a more marked effect at the international scale, where we estimate the number of case importations to be reduced by 80% until the end of February. Modeling results also indicate that sustained 90% travel restrictions to and from Mainland China only modestly affect the epidemic trajectory unless combined with a 50% or higher reduction of transmission in the community. ### Competing Interest Statement All authors have completed the ICMJE uniform disclosure form at and declare: no support from any organisation for the submitted work; MEH reports grants from National Institute of General Medical Sciences, during the conduct of the study; AV reports grants and personal fees from Metabiota inc., outside the submitted work; MC and APyP report grants from Metabiota inc., outside the submitted work; HY reports grants from Glaxosmithkline (China) Investment Co., Ltd, grants from Yichang HEC Changjiang Pharmaceutical Co., Ltd, grants from Sanofi Pasteur, grants from Shanghai Roche Pharmaceuticals Company, outside the submitted work. No other relationships or activities that could appear to have influenced the submitted work. ### Funding Statement MEH acknowledge the support of the MIDAS-U54GM111274. SM and MA acknowledge support from the EU H2020 MOOD project. CG and LR acknowledge support from the EU H2020 Icarus project. The findings and conclusions in this study are those of the authors and do not necessarily represent the official position of the funding agencies, the National Institutes of Health or U.S. Department of Health and Human Services. ### Author Declarations All relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript. Yes All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The datasets generated and analysed during the current study are available from the corresponding author on reasonable request.

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