The global dissemination of COVID-19 through two coexisting international transmission patterns

The global dissemination of COVID-19 through two coexisting international transmission patterns | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The global dissemination of COVID-19 through two coexisting international transmission patterns Hiroyasu Inoue This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7395229/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Mar, 2026 Read the published version in EPJ Data Science → Version 1 posted 10 You are reading this latest preprint version Abstract The novel coronavirus SARS-CoV-2, commonly referred to as COVID-19, triggered a global pandemic. Although understanding the nature of international infection spread is critically important, extracting diffusion networks from observational data is challenging due to the inherent complexity of the phenomenon.In this study, we investigate the global infection process, including time delays, using worldwide infection case data collected from January 3, 2020, to December 31, 2022. We analyze the data using complex Hilbert principal component analysis, which captures not only concurrent relationships among variables but also leading and lagging dynamics. We then examine interactions among countries in relation to six factors: geography, population, GDP, stringency of countermeasures, vaccination rates, and government type. The results reveal that two primary trends coexisted during the period: one in 2020 and another in 2021 and 2022, with their dominance alternating over time. Specifically, in 2020, European, high-income, and democratic countries led the first trend and were typically associated with higher transmission levels.In contrast, in 2021 and 2022, African and American countries, particularly those with lower income levels, exhibited leading trends. We also find that, while internal countermeasures may have helped suppress domestic case numbers, they did not influence the trend of international spread. Furthermore, although vaccination became widespread in 2021, it likewise did not alter the pattern of international transmission. COVID-19 Interactions Principal component analysis Infection spread Country Full Text Additional Declarations No competing interests reported. Supplementary Files SI.pdf Cite Share Download PDF Status: Published Journal Publication published 16 Mar, 2026 Read the published version in EPJ Data Science → Version 1 posted Editorial decision: Revision requested 02 Nov, 2025 Reviews received at journal 29 Oct, 2025 Reviews received at journal 27 Oct, 2025 Reviewers agreed at journal 06 Oct, 2025 Reviewers agreed at journal 03 Oct, 2025 Reviewers agreed at journal 02 Oct, 2025 Reviewers invited by journal 01 Oct, 2025 Editor assigned by journal 20 Aug, 2025 Submission checks completed at journal 20 Aug, 2025 First submitted to journal 17 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7395229","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":528025494,"identity":"7c37d37d-9591-48f1-b751-63a152d776bc","order_by":0,"name":"Hiroyasu Inoue","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA90lEQVRIiWNgGAWjYBACNjBZAWUwNqBJ4NZyhhQtYMDYBmM04FMGBXzSzcckPs6rtefjP8AmwbjjsJy8ewPjhx8MfHk4HSZzLE1y5rbjiW0SCUAtZw4bG545wCzZw8BWjFOLRI6ZNO+2Y0D1DGzSf9sOJ26ckcAgDZRIxOVIsJa/c47Zs4EdBtHC/JugFsaGGmAIJEC0zAe6kIAtacmWPccOAP2S2GzB2JZubMBzsM2yxwC3X+RnJB+88aOmzl6+//DBG4xt1nLy7c2Hb/yoOIYzxKDgMAM0UpoZDA6AGAbHEghoqUMw5CF+qCGkZRSMglEwCkYOAAAjGE3+KLasiAAAAABJRU5ErkJggg==","orcid":"","institution":"University of Hyogo","correspondingAuthor":true,"prefix":"","firstName":"Hiroyasu","middleName":"","lastName":"Inoue","suffix":""}],"badges":[],"createdAt":"2025-08-18 03:08:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7395229/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7395229/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1140/epjds/s13688-026-00639-0","type":"published","date":"2026-03-16T15:57:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":93463316,"identity":"027367ae-279a-4da0-8791-e6d56332c64a","added_by":"auto","created_at":"2025-10-14 06:46:37","extension":"json","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":3719,"visible":true,"origin":"","legend":"","description":"","filename":"a6b12966a83e402face16b9634133041.json","url":"https://assets-eu.researchsquare.com/files/rs-7395229/v1/03012f02582c21b13c7a441f.json"},{"id":105224976,"identity":"bf28305c-70ec-41fd-bee9-86b1883e309c","added_by":"auto","created_at":"2026-03-23 16:19:07","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":905780,"visible":true,"origin":"","legend":"","description":"","filename":"submit.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7395229/v1_covered_fe3ed1f7-9034-4cdd-a5ab-4b11abd1f6a4.pdf"},{"id":93463317,"identity":"0bb2b204-59ce-4de9-adc8-c2e56c2483fa","added_by":"auto","created_at":"2025-10-14 06:46:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":1915619,"visible":true,"origin":"","legend":"","description":"","filename":"SI.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7395229/v1/87b8e5254d8dba32255f5383.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The global dissemination of COVID-19 through two coexisting international transmission patterns","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"epj-data-science","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"epds","sideBox":"Learn more about [EPJ Data Science](https://epjdatascience.springeropen.com/)","snPcode":"13688","submissionUrl":"https://submission.springernature.com/new-submission/13688/3","title":"EPJ Data Science","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"COVID-19, Interactions, Principal component analysis, Infection spread, Country","lastPublishedDoi":"10.21203/rs.3.rs-7395229/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7395229/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe novel coronavirus SARS-CoV-2, commonly referred to as COVID-19, triggered a global pandemic. 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