{
  "abstract": "The increasing interconnectedness of the modern world calls for globally equitable solutions to combat pandemic challenges. However, we have seen a tendency in recent decades for high-income countries to resort to “vaccine nationalism,” hoarding vaccine production to the detriment of lower-income countries. In addition, vaccine nationalism can prove detrimental to hoarding countries in the long term, as inequitable global vaccine distribution during the COVID-19 risked exacerbating the rise of harmful immune-escape variants that largely counteracted the original benefits of vaccine hoarding. Thus, vaccine hoarding may create a problem of time preference for a vaccine-producing country, where countries heavily discounting the future would opt for vaccine hoarding while countries lightly discounting the future would opt for vaccine sharing. Using a novel modeling framework integrating epidemiological, evolutionary, and economic processes, we demonstrate how high temporal discounting, low levels of outgroup prosociality, and high vaccine-distribution costs for low-income countries can promote vaccine-hoarding tendencies. We further show how these factors interact with epidemiological and evolutionary parameters to incentivize vaccine sharing in different ways: in some parameter regimes, vaccine sharing helps by reducing variant infections, while in others, vaccine sharing helps by reducing the probability of initial variant emergence. As a result, the optimal fraction of vaccines a country should share in our model is a bimodal function of the pathogen’s transmissibility. We thus provide a nuanced, model-based exploration of how various factors may contribute to vaccine nationalism’s emergence, emphasizing the need for international organizations to coordinate global vaccination responses to future pandemics. Author summary: In the wake of the extreme inequities in global vaccine distribution that arose during the COVID-19 pandemic, it is necessary to analyze the factors that drove countries to “vaccine nationalism” to ensure more equitable vaccine distribution for future pandemic challenges. Through a novel modeling framework combining epidemiological, evolutionary, and economic processes, we identify crucial economic and sociological factors that can promote vaccine-hoarding tendencies in high-income countries, despite the threat of viral evolution which could reverse the short-term benefits of vaccine hoarding. In particular, we highlight that shortsighted policies neglecting the roles of viral evolution and transmission in other countries promote vaccine hoarding, to the eventual detriment of the vaccine-hoarding country. To minimize global disease burden and probability of viral immune escape, we emphasize the need for international collaboration in overseeing global vaccine distribution, with policies that incorporate lower temporal discount rates, more prosocial thinking, and aid to vaccine-distribution infrastructure in lower-income countries.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America",
    "Department of Plant Biology, University of Vermont, Burlington, Vermont, United States of America",
    "Vermont Complex Systems Institute, University of Vermont, Burlington, Vermont, United States of America",
    "High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, United States of America",
    "Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark",
    "PandemiX Center, Roskilde University, Roskilde, Denmark"
  ],
  "article_type": "Research Article",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Ari S. Freedman"
    },
    {
      "affs": [
        1
      ],
      "name": "Bjarke Frost Nielsen"
    },
    {
      "affs": [
        2
      ],
      "name": "Chadi M. Saad-Roy"
    },
    {
      "affs": [
        3
      ],
      "name": "Bryan T. Grenfell"
    },
    {
      "affs": [
        4
      ],
      "name": "C. Jessica E. Metcalf"
    },
    {
      "affs": [
        5
      ],
      "name": "Simon A. Levin"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/92h80mf5hy2cq.bib",
  "cited_by": 0,
  "doi": "10.1371/journal.pcbi.1014466",
  "fulltext_url": "https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1014466",
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  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
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      "3306|Vaccine Coverage and Hesitancy"
    ],
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      "/Biology and life sciences/Evolutionary biology/Evolutionary immunology"
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      "/Biology and life sciences/Microbiology/Virology/Viral evolution"
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    [
      "plos",
      "/Biology and life sciences/Microbiology/Virology/Viral vaccines"
    ],
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      "/Biology and life sciences/Neuroscience/Cognitive science/Cognitive psychology/Social cognition/Prosocial behavior"
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    ],
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      "/Biology and life sciences/Psychology/Cognitive psychology/Social cognition/Prosocial behavior"
    ],
    [
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      "/Biology and life sciences/Psychology/Social psychology/Social cognition/Prosocial behavior"
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      "plos",
      "/Medicine and health sciences/Epidemiology/Pandemics"
    ],
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      "plos",
      "/Medicine and health sciences/Immunology/Vaccination and immunization"
    ],
    [
      "plos",
      "/Medicine and health sciences/Immunology/Vaccination and immunization/Vaccine development"
    ],
    [
      "plos",
      "/Medicine and health sciences/Medical conditions/Infectious diseases/Infectious disease control/Vaccines"
    ],
    [
      "plos",
      "/Medicine and health sciences/Medical conditions/Infectious diseases/Infectious disease control/Vaccines/Viral vaccines"
    ],
    [
      "plos",
      "/Medicine and health sciences/Public and occupational health/Preventive medicine/Vaccination and immunization"
    ],
    [
      "plos",
      "/Medicine and health sciences/Public and occupational health/Preventive medicine/Vaccination and immunization/Vaccine development"
    ],
    [
      "plos",
      "/Social sciences/Psychology/Behavior/Prosocial behavior"
    ],
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      "plos",
      "/Social sciences/Psychology/Cognitive psychology/Social cognition/Prosocial behavior"
    ],
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      "/Social sciences/Psychology/Social psychology/Social cognition/Prosocial behavior"
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  "pdf_url": "https://journals.plos.org/ploscompbiol/article/file?id=10.1371/journal.pcbi.1014466&type=printable",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-31",
  "publisher": "Public Library of Science",
  "ris": "https://research.draconitic.com/paper/92h80mf5hy2cq.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:02Z",
      "native_id": "10.1371/journal.pcbi.1014466",
      "source": "plos",
      "url": "https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1014466"
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  "subjects": [
    {
      "field": "biology",
      "origin": "plos:immunology",
      "subfield": "immunology"
    },
    {
      "field": "biology",
      "origin": "plos:microbiology",
      "subfield": "microbiology"
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    {
      "field": "medicine",
      "origin": "plos:epidemiology",
      "subfield": "epidemiology-public-health"
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  ],
  "title": "Economic factors promoting vaccine nationalism in the face of viral evolution",
  "title_text": "Economic factors promoting vaccine nationalism in the face of viral evolution",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:02Z",
  "url": "https://research.draconitic.com/paper/92h80mf5hy2cq",
  "venue": "PLOS Computational Biology",
  "versions": []
}