Risk Analysis of Measles Outbreaks in Bulgaria and Romania for the Period 2000 to 2023: A Comparative Study.

Risk Analysis of Measles Outbreaks in Bulgaria and Romania for the Period 2000 to 2023: A Comparative Study. | 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 Risk Analysis of Measles Outbreaks in Bulgaria and Romania for the Period 2000 to 2023: A Comparative Study. Ognyan Kounchev, Georgi Simeonov, Zhana Kuncheva, Radka Argirova, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6498892/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 12 You are reading this latest preprint version Abstract Purpose Measles is a highly contagious but vaccine-preventable infectious disease. According to the ECDC report from 16th February 2024 “Measles on the rise in the EU/EEA: considerations for public health response”, urgent action is required to address the increasing spread of measles and insufficient vaccination coverage across the EU. The main objective of the present re-search is a comparative analysis of measles outbreak risk in two neighboring countries with intensive economic relations - Bulgaria and Romania. Our research is part of a larger project for measles outbreak risk assessment in Bulgaria’s neighboring countries to gain broader in-sight on the potential threats in the near future. Methods Data from a 50-year period was collected on immunization coverage and demographic dynamics in Bulgaria and Romania. A mathematical model is applied to estimate the immunization coverage and demographic parameters on yearly basis. This allows us to calculate with satisfactory precision the accumulation of susceptible persons tracing at least 20 years back in the history. The core of the model is the calculation of an annual Risk Index defined as the ratio of all susceptible individuals to the total population. Results The Risk Index curves for measles outbreak in Bulgaria and Romania were calculated for the period 2000 to 2023. The Risk Index curve for Bulgaria reveals a concerning increase after 2015, with particularly alarming values projected for 2017 and later. The results of the Risk Index for Romania are also alarming after 2016. In 2023, the Risk Index for Bulgaria hits 7.55%, whereas in Romania it hits 8.1%. Conclusion Comparing the findings from the Risk Index to the real data from measles outbreaks shows that the Risk Index is a good indicator for risk of measles outbreak. It can help the health authorities to forecast potential measles outbreaks. An important consideration is that the vaccination coverage should be simultaneously monitored with the demography, which may be missed even by professionals. measles vaccination outbreaks risk indicator Risk Index Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 09 May, 2025 Reviews received at journal 09 May, 2025 Reviews received at journal 08 May, 2025 Reviewers agreed at journal 04 May, 2025 Reviewers agreed at journal 02 May, 2025 Reviewers agreed at journal 02 May, 2025 Reviewers agreed at journal 01 May, 2025 Reviewers agreed at journal 01 May, 2025 Reviewers invited by journal 01 May, 2025 Editor assigned by journal 01 May, 2025 Submission checks completed at journal 01 May, 2025 First submitted to journal 21 Apr, 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-6498892","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":451934365,"identity":"b02df2d3-751b-4779-8d59-3c5ae25ba913","order_by":0,"name":"Ognyan Kounchev","email":"","orcid":"","institution":"Institute of Mathematics and Informatics, Bulgarian Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Ognyan","middleName":"","lastName":"Kounchev","suffix":""},{"id":451934366,"identity":"472a189f-06d2-4022-af73-765dc92f592a","order_by":1,"name":"Georgi Simeonov","email":"","orcid":"","institution":"Institute of Mathematics and Informatics, Bulgarian Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Georgi","middleName":"","lastName":"Simeonov","suffix":""},{"id":451934367,"identity":"36ea732a-1757-45c9-b5e9-221536f82e99","order_by":2,"name":"Zhana Kuncheva","email":"","orcid":"","institution":"bioXcelerate, a division of Optima Partners","correspondingAuthor":false,"prefix":"","firstName":"Zhana","middleName":"","lastName":"Kuncheva","suffix":""},{"id":451934368,"identity":"1200075d-c848-4b37-9d12-cbf0baa9a1ca","order_by":3,"name":"Radka Argirova","email":"","orcid":"","institution":"Department of Clinical Laboratory, Sofia University St Kliment Ohridski Faculty of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Radka","middleName":"","lastName":"Argirova","suffix":""},{"id":451934369,"identity":"49488553-01ab-4c53-ba44-8be8b409d810","order_by":4,"name":"Trifon Valkov","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2UlEQVRIie3PIQvCQBjG8ecYuODO1cnQz7AmguBX0WIUxGK8YzCLYp3Nj6AIY03h6sSqTTELLhpETxQ0ebMJ3j9c+/G8B+h0PxlhJ/k2YIDsCAM8FbBAePgkhpeRgDwIkHMykborOEtjtG0z3+qdY4GKPVGsFJqcjxN0iz6NtsNEoBruFMQi/QMN0JwKGm1o0IK3WSoJ9+9kIUnn8hWZGjQyaFCDt2YKkhD5F0lCQeduKalZ1fCzgDkw9yyVZDRazdJj7JQrtuKwZ9fXLJxGJvJexhWdTqf7n26ebkRMeyqXfwAAAABJRU5ErkJggg==","orcid":"","institution":"Department of Infectious Diseases, Medical University-Sofia Faculty of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Trifon","middleName":"","lastName":"Valkov","suffix":""}],"badges":[],"createdAt":"2025-04-21 22:53:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6498892/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6498892/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":82102365,"identity":"344d4548-d580-46f7-9eef-cd9bac2b7b28","added_by":"auto","created_at":"2025-05-06 19:14:40","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":828044,"visible":true,"origin":"","legend":"","description":"","filename":"PAPERROMANIAbasedonBulgarianVER4PAPER1RISKINDEXVER16FINALCORRECTIONS2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6498892/v1_covered_72a584f2-9aa2-4abd-b692-98364babd6f6.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eRisk Analysis of Measles Outbreaks in Bulgaria and Romania for the Period 2000 to 2023: A Comparative Study.\u003c/p\u003e","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":"journal-of-epidemiology-and-global-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Journal of Epidemiology and Global Health](https://www.springer.com/journal/44197)","snPcode":"44197","submissionUrl":"https://submission.nature.com/new-submission/44197/3","title":"Journal of Epidemiology and Global Health","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"measles, vaccination, outbreaks, risk indicator, Risk Index","lastPublishedDoi":"10.21203/rs.3.rs-6498892/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6498892/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003ePurpose\u003c/b\u003e\u003c/p\u003e \u003cp\u003eMeasles is a highly contagious but vaccine-preventable infectious disease. According to the ECDC report from 16th February 2024 \u0026ldquo;Measles on the rise in the EU/EEA: considerations for public health response\u0026rdquo;, urgent action is required to address the increasing spread of measles and insufficient vaccination coverage across the EU. The main objective of the present re-search is a comparative analysis of measles outbreak risk in two neighboring countries with intensive economic relations - Bulgaria and Romania. Our research is part of a larger project for measles outbreak risk assessment in Bulgaria\u0026rsquo;s neighboring countries to gain broader in-sight on the potential threats in the near future.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eData from a 50-year period was collected on immunization coverage and demographic dynamics in Bulgaria and Romania. A mathematical model is applied to estimate the immunization coverage and demographic parameters on yearly basis. This allows us to calculate with satisfactory precision the accumulation of susceptible persons tracing at least 20 years back in the history. The core of the model is the calculation of an annual Risk Index defined as the ratio of all susceptible individuals to the total population.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThe Risk Index curves for measles outbreak in Bulgaria and Romania were calculated for the period 2000 to 2023. The Risk Index curve for Bulgaria reveals a concerning increase after 2015, with particularly alarming values projected for 2017 and later. The results of the Risk Index for Romania are also alarming after 2016. In 2023, the Risk Index for Bulgaria hits 7.55%, whereas in Romania it hits 8.1%.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e \u003cp\u003eComparing the findings from the Risk Index to the real data from measles outbreaks shows that the Risk Index is a good indicator for risk of measles outbreak. It can help the health authorities to forecast potential measles outbreaks. An important consideration is that the vaccination coverage should be simultaneously monitored with the demography, which may be missed even by professionals.\u003c/p\u003e","manuscriptTitle":"Risk Analysis of Measles Outbreaks in Bulgaria and Romania for the Period 2000 to 2023: A Comparative Study.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-06 18:42:30","doi":"10.21203/rs.3.rs-6498892/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-05-09T11:25:13+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-09T11:10:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-08T09:04:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"134310312823681921954129029350453725505","date":"2025-05-04T20:17:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"242019616490028508989304583280587790520","date":"2025-05-02T12:00:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"148732382863408667160791835658330755147","date":"2025-05-02T09:39:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"127385210762195244024368745535076762057","date":"2025-05-01T17:04:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"80816345112907005617402050369226420911","date":"2025-05-01T16:13:02+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-01T14:27:53+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-01T14:26:02+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-01T05:14:22+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Epidemiology and Global Health","date":"2025-04-21T22:45:50+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-epidemiology-and-global-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Journal of Epidemiology and Global Health](https://www.springer.com/journal/44197)","snPcode":"44197","submissionUrl":"https://submission.nature.com/new-submission/44197/3","title":"Journal of Epidemiology and Global Health","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cbc55e13-d212-4dea-98ba-71e831f1247b","owner":[],"postedDate":"May 6th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-06-07T10:23:24+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-06 18:42:30","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6498892","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6498892","identity":"rs-6498892","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}