Salivary antibodies mirror systemic humoral immunity to SARS CoV-2 and reveal sex-specific differences in salivary anti-spike IgA and IgG levels

Salivary antibodies mirror systemic humoral immunity to SARS CoV-2 and reveal sex-specific differences in salivary anti-spike IgA and IgG levels | 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 Article Salivary antibodies mirror systemic humoral immunity to SARS CoV-2 and reveal sex-specific differences in salivary anti-spike IgA and IgG levels Joshua Flynn, Eolann Dinneen, Clo O’Riordan, Joanna Szafran, Matt Power, and 10 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7197612/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Durable antibody responses are essential for long-term protection against SARS-CoV-2. We assessed the utility of point-of-care lateral flow tests (LFTs) versus ELISA in monitoring systemic and mucosal immunity and explored saliva as a surrogate for serum antibody measurement. 450 participants were recruited in a university and serum and saliva samples were analysed for anti-Spike IgA and IgG antibodies using ELISA, and for nucleocapsid (N) and neutralising Spike antibodies via LFT. Despite only 46% self-reporting prior infection, 95% had detectable N antibodies. Serum demonstrated higher anti-Spike IgA and IgG positivity than saliva. Moderate correlations between serum and salivary IgA and IgG were observed. LFT band intensity significantly correlated with ELISA-derived antibody levels. Sex-specific differences in salivary anti-Spike IgA and IgG levels were identified, with males displaying higher levels in early post-exposure periods. These findings support LFTs and saliva sampling as accessible tools for monitoring SARS-CoV-2 immunity and guiding booster vaccination strategies. Health sciences/Biomarkers Health sciences/Diseases Biological sciences/Immunology Health sciences/Medical research Biological sciences/Microbiology Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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-7197612","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":496249155,"identity":"aa1df007-0e7b-44d8-89d8-840b1ce4ab9b","order_by":0,"name":"Joshua Flynn","email":"","orcid":"","institution":"Trinity Translational Medicine Institute, Trinity College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Joshua","middleName":"","lastName":"Flynn","suffix":""},{"id":496249156,"identity":"83d5c77b-7e69-4cdd-9336-1f7d97553241","order_by":1,"name":"Eolann Dinneen","email":"","orcid":"","institution":"University College Cork","correspondingAuthor":false,"prefix":"","firstName":"Eolann","middleName":"","lastName":"Dinneen","suffix":""},{"id":496249157,"identity":"2b76ba15-82a7-47f8-89d6-67aed8c744cd","order_by":2,"name":"Clo O’Riordan","email":"","orcid":"","institution":"University College Cork","correspondingAuthor":false,"prefix":"","firstName":"Clo","middleName":"","lastName":"O’Riordan","suffix":""},{"id":496249158,"identity":"3df07144-fbdb-436e-b71d-29bdac92d4a0","order_by":3,"name":"Joanna Szafran","email":"","orcid":"","institution":"University College Cork","correspondingAuthor":false,"prefix":"","firstName":"Joanna","middleName":"","lastName":"Szafran","suffix":""},{"id":496249160,"identity":"0afb277c-80b5-4d27-84f3-122c029e820c","order_by":4,"name":"Matt Power","email":"","orcid":"","institution":"University College Cork","correspondingAuthor":false,"prefix":"","firstName":"Matt","middleName":"","lastName":"Power","suffix":""},{"id":496249162,"identity":"9c985bcf-4ea8-4f83-b2b1-6a2d312bdcc4","order_by":5,"name":"Muireann Hickey","email":"","orcid":"","institution":"University College Cork","correspondingAuthor":false,"prefix":"","firstName":"Muireann","middleName":"","lastName":"Hickey","suffix":""},{"id":496249164,"identity":"d091a48f-cc6d-498e-b3e7-724225eeaa0d","order_by":6,"name":"Siobhan Gargan","email":"","orcid":"","institution":"Trinity Translational Medicine Institute, Trinity College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Siobhan","middleName":"","lastName":"Gargan","suffix":""},{"id":496249166,"identity":"a0fdc175-cc1c-4662-9ee1-e649fc2f7d1b","order_by":7,"name":"William McCormack","email":"","orcid":"","institution":"Trinity Translational Medicine Institute, Trinity College Dublin","correspondingAuthor":false,"prefix":"","firstName":"William","middleName":"","lastName":"McCormack","suffix":""},{"id":496249167,"identity":"3c5b1b16-85cd-423c-9086-15cec997ee73","order_by":8,"name":"Orla Sheils","email":"","orcid":"","institution":"Trinity Translational Medicine Institute, Trinity College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Orla","middleName":"","lastName":"Sheils","suffix":""},{"id":496249169,"identity":"bf4a89d8-f293-4b32-881e-eeae3bc7cd3e","order_by":9,"name":"Breda Smyth","email":"","orcid":"","institution":"HSE West","correspondingAuthor":false,"prefix":"","firstName":"Breda","middleName":"","lastName":"Smyth","suffix":""},{"id":496249170,"identity":"ea91aeda-997d-4362-97ca-d282e411eb81","order_by":10,"name":"Mary Horgan","email":"","orcid":"","institution":"University College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Mary","middleName":"","lastName":"Horgan","suffix":""},{"id":496249171,"identity":"e5631e80-e051-47ee-b0ac-6add4c0042f1","order_by":11,"name":"Michael Byrne","email":"","orcid":"","institution":"University College Cork","correspondingAuthor":false,"prefix":"","firstName":"Michael","middleName":"","lastName":"Byrne","suffix":""},{"id":496249172,"identity":"27f61526-1511-411b-b64c-b22be73a54a5","order_by":12,"name":"Niall O’Leary","email":"","orcid":"","institution":"University College Cork","correspondingAuthor":false,"prefix":"","firstName":"Niall","middleName":"","lastName":"O’Leary","suffix":""},{"id":496249173,"identity":"0d86755c-c598-4e91-bffc-a4326dedf399","order_by":13,"name":"Aideen Long","email":"","orcid":"","institution":"Trinity Translational Medicine Institute, Trinity College Dublin","correspondingAuthor":false,"prefix":"","firstName":"Aideen","middleName":"","lastName":"Long","suffix":""},{"id":496249174,"identity":"d960debe-e31c-4b69-b492-effbba958a95","order_by":14,"name":"John MacSharry","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYBACxgYwdQDMfgAi2UjRwmxAlBYoAGthkyBKLXMDd+KHH3/uyJvPPmNWzVNjx8DH3kDIYbybJXvbnhnOOZdjdpvnWDIDG88Bglo2SDM2HGacwcNjdpu34QDQeQmEbfnN8OewPUhLMViL/AOCWrZJM7AdTgRpYYbYgl8HA2Mz7zbL3rbDyTN42Iol5xxL5mHjIeAww/bezTd+/DlsO4OHeeOHNzV2cvLtBwhoaYYzOcAxyUPAWQwM8ggm+wOCqkfBKBgFo2BkAgCiYDy9iNEdVAAAAABJRU5ErkJggg==","orcid":"","institution":"University College Cork","correspondingAuthor":true,"prefix":"","firstName":"John","middleName":"","lastName":"MacSharry","suffix":""}],"badges":[],"createdAt":"2025-07-23 14:53:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7197612/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7197612/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":97368645,"identity":"fb156a2b-7a3f-41a1-b816-9b51d6cf99a7","added_by":"auto","created_at":"2025-12-03 16:22:41","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":748068,"visible":true,"origin":"","legend":"","description":"","filename":"UniCoVAbspaperinclFigures29072025.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7197612/v1_covered_2c1c0405-cbc4-4df8-acf3-3b8cba454d5a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Salivary antibodies mirror systemic humoral immunity to SARS CoV-2 and reveal sex-specific differences in salivary anti-spike IgA and IgG levels","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7197612/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7197612/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eDurable antibody responses are essential for long-term protection against SARS-CoV-2. We assessed the utility of point-of-care lateral flow tests (LFTs) versus ELISA in monitoring systemic and mucosal immunity and explored saliva as a surrogate for serum antibody measurement. 450 participants were recruited in a university and serum and saliva samples were analysed for anti-Spike IgA and IgG antibodies using ELISA, and for nucleocapsid (N) and neutralising Spike antibodies via LFT. Despite only 46% self-reporting prior infection, 95% had detectable N antibodies. Serum demonstrated higher anti-Spike IgA and IgG positivity than saliva. Moderate correlations between serum and salivary IgA and IgG were observed. LFT band intensity significantly correlated with ELISA-derived antibody levels. Sex-specific differences in salivary anti-Spike IgA and IgG levels were identified, with males displaying higher levels in early post-exposure periods. These findings support LFTs and saliva sampling as accessible tools for monitoring SARS-CoV-2 immunity and guiding booster vaccination strategies.\u003c/p\u003e","manuscriptTitle":"Salivary antibodies mirror systemic humoral immunity to SARS CoV-2 and reveal sex-specific differences in salivary anti-spike IgA and IgG levels","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-20 18:11:35","doi":"10.21203/rs.3.rs-7197612/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4729c7f3-b587-441c-9b1a-2631598df7a4","owner":[],"postedDate":"August 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":52706571,"name":"Health sciences/Biomarkers"},{"id":52706572,"name":"Health sciences/Diseases"},{"id":52706573,"name":"Biological sciences/Immunology"},{"id":52706574,"name":"Health sciences/Medical research"},{"id":52706575,"name":"Biological sciences/Microbiology"}],"tags":[],"updatedAt":"2025-12-03T01:08:28+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-20 18:11:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7197612","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7197612","identity":"rs-7197612","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}