Protecting an island nation from extreme pandemic threats: Proof-of-concept around border closure as an intervention

PLOS ONE, Dec 2019

Background Countries are well advised to prepare for future pandemic risks (e.g., pandemic influenza, novel emerging agents or synthetic bioweapons). These preparations do not typically include planning for complete border closure. Even though border closure may not be instituted in time, and can fail, there might still plausible chances of success for well organized island nations. Objective To estimate costs and benefits of complete border closure in response to new pandemic threats, at an initial proof-of-concept level. New Zealand was used as a case-study for an island country. Methods An Excel spreadsheet model was developed to estimate costs and benefits. Case-study specific epidemiological data was sourced from past influenza pandemics. Country-specific healthcare cost data, valuation of life, and lost tourism revenue were imputed (with lost trade also in scenario analyses). Results For a new pandemic equivalent to the 1918 influenza pandemic (albeit with half the mortality rate, “Scenario A”), it was estimated that successful border closure for 26 weeks provided a net societal benefit (e.g., of NZ$11.0 billion, USD$7.3 billion). Even in the face of a complete end to trade, a net benefit was estimated for scenarios where the mortality rate was high (e.g., at 10 times the mortality impact of “Scenario A”, or 2.75% of the country’s population dying) giving a net benefit of NZ$54 billion (USD$36 billion). But for some other pandemic scenarios where trade ceased, border closure resulted in a net negative societal value (e.g., for “Scenario A” times three for 26 weeks of border closure–but not for only 12 weeks of closure when it would still be beneficial). Conclusions This “proof-of-concept” work indicates that more detailed cost-benefit analysis of border closure in very severe pandemic situations for some island nations is probably warranted, as this course of action might sometimes be worthwhile from a societal perspective.

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Protecting an island nation from extreme pandemic threats: Proof-of-concept around border closure as an intervention

June Protecting an island nation from extreme pandemic threats: Proof-of-concept around border closure as an intervention Matt Boyd 0 1 Michael G. Baker 0 Osman D. Mansoor 0 Giorgi Kvizhinadze 0 Nick Wilson 0 0 Editor: David Hutton, University of Michigan , UNITED STATES 1 Adapt Research Ltd , Wellington , New Zealand , 2 Department of Public Health, University of Otago , Wellington , New Zealand, 3 39 Mortimer Tce, Wellington , New Zealand Background Countries are well advised to prepare for future pandemic risks (e.g., pandemic influenza, novel emerging agents or synthetic bioweapons). These preparations do not typically include planning for complete border closure. Even though border closure may not be instituted in time, and can fail, there might still plausible chances of success for well organized island nations. To estimate costs and benefits of complete border closure in response to new pandemic threats, at an initial proof-of-concept level. New Zealand was used as a case-study for an island country. a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: The first author (MB) is the sole employee (and owner) of Adapt Research Ltd. Adapt Research Ltd provided support in the form of salary for MB, but the study was otherwise selffunded by the authors. The authors received no additional university or external funding. Adapt Research Ltd had no additional role in the study design, data collection and analysis, decision to Objective Methods Results An Excel spreadsheet model was developed to estimate costs and benefits. Case-study specific epidemiological data was sourced from past influenza pandemics. Country-specific healthcare cost data, valuation of life, and lost tourism revenue were imputed (with lost trade also in scenario analyses). For a new pandemic equivalent to the 1918 influenza pandemic (albeit with half the mortality rate, ªScenario Aº), it was estimated that successful border closure for 26 weeks provided a net societal benefit (e.g., of NZ$11.0 billion, USD$7.3 billion). Even in the face of a complete end to trade, a net benefit was estimated for scenarios where the mortality rate was high (e.g., at 10 times the mortality impact of ªScenario Aº, or 2.75% of the country's population dying) giving a net benefit of NZ$54 billion (USD$36 billion). But for some other pandemic scenarios where trade ceased, border closure resulted in a net negative societal value (e.g., for ªScenario Aº times three for 26 weeks of border closure±but not for only 12 weeks of closure when it would still be beneficial). publish, or preparation of the manuscript. The specific roles of the authors are articulated in the 'author contributions' section. Competing interests: The first author (MB) is the sole employee (and owner) of Adapt Research Ltd. This does not alter our adherence to PLOS ONE policies on sharing data and materials. Conclusions This ªproof-of-conceptº work indicates that more detailed cost-benefit analysis of border closure in very severe pandemic situations for some island nations is probably warranted, as this course of action might sometimes be worthwhile from a societal perspective. Introduction A widespread view is that country border closures have a limited, if any, role in preventing the spread of infectious diseases [ 1 ]. Indeed, the World Health Organization (WHO) advice is that even though unaffected countries may be able to delay the introduction of the infectious agent by imposing severe limits on international travel, border closure is unlikely to be able to prevent importation, and can have huge economic and personal costs. Such border closures can potentially damage trade and economies with one US study estimating the GDP halving from one year's closure that suspended 95% of imports and exports [ 2 ]. Yet, historically there is evidence that border closure can be effective in preventing the spread of pandemic influenza: successful control of the 1918±19 influenza pandemic in various Pacific islands [ 3 ] and US military bases [ 4 ]. Internal border control was also helpful for Iceland in that pandemic [ 5 ]. Theoretical studies of small island nations also suggest that stopping travel in response to an influenza pandemic might be helpful in those with low travel volumes [ 6 ]. Furthermore, it is biologically plausible that a new infectious agent (e.g., a synthetic bioweapon or an existing agent like Ebola that became more infectious), could be of such severity that attempting border closure could be a rational choice for a country, particularly for island nations. That is especially if that closure decision could be made in time before the agent had already entered the island nation in sufficient numbers to prevent local control and that border controls could be successfully maintained for the period of risk. Clearly (...truncated)


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Matt Boyd, Michael G. Baker, Osman D. Mansoor, Giorgi Kvizhinadze, Nick Wilson. Protecting an island nation from extreme pandemic threats: Proof-of-concept around border closure as an intervention, PLOS ONE, 2017, Volume 12, Issue 6, DOI: 10.1371/journal.pone.0178732