{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"medRxiv"}],"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T22:38:38Z","timestamp":1792795118567,"version":"4.5.0"},"posted":{"date-parts":[[2025,5,26]]},"group-title":"Epidemiology","reference-count":33,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2025,5,26]],"date-time":"2025-05-26T00:00:00Z","timestamp":1748217600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"name":"National Institutes of Health","award":["75N93021C00015"],"award-info":[{"award-number":["75N93021C00015"]}]},{"name":"Food and Health Bureau of the Hong Kong SAR Government","id":[{"id":"https:\/\/ror.org\/03qh32912","id-type":"ROR","asserted-by":"crossref"}]},{"name":"Research Grants Council from the University Grants Committee of Hong Kong","id":[{"id":"https:\/\/ror.org\/00djwmt25","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,10,17]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>Reduced influenza transmission during the COVID-19 pandemic prompted concern about waning of population immunity that could lead to subsequent surges in circulation. We compared longitudinal influenza antibody titers in Michigan and Hong Kong, two regions with reduced influenza transmission during the COVID-19 pandemic.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>In two prospective cohort studies (HIVE, Michigan; EPI-HK, Hong Kong), we analyzed longitudinal serum samples collected from 2020 through 2023 from participants without influenza infection or vaccination. Sera were tested using hemagglutination inhibition assays (HAI) and microneutralization (MN) against vaccine strains. Two-year fold changes in titers were estimated using multivariable power-law models adjusted for age and baseline titer.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>We analyzed 173 sera from 57 HIVE participants and 259 sera from 60 EPI-HK participants. Initial HAI geometric mean titers ranged from 12.3\u2013123.4 in HIVE and 6.3\u201340.9 in EPI-HK. Among those with &gt;1:40 baseline titers in HIVE, fold-change estimates indicated waning for H1N1 strains, including A\/Brisbane (0.70 [95% CI: 0.56,0.86]), A\/Idaho (0.40 [0.32,0.50]), and A\/Michigan (0.43 [0.34,0.52]), while H3N2 and influenza B showed minimal or no waning. In EPI-HK, fold-change estimates demonstrated heterogeneous patterns by strain for H1N1, and waning for selected H3N2 strains, including A\/Cambodia (0.44 [0.29,0.65]) and A\/Singapore (0.48 [0.33,0.69]). MN results were consistent with HAI findings.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>Influenza antibody responses during the pandemic showed heterogeneous, strain-specific changes rather than uniform decline. These findings suggest that population immunity was maintained for many strains despite reduced viral circulation, with waning occurring in particular strains and varying by population.<\/jats:p>\n                <\/jats:sec>\n                <jats:sec>\n                  <jats:title>Summary<\/jats:title>\n                  <jats:p>Influenza antibody responses during the pandemic showed heterogeneous, strain-specific changes rather than uniform decline in Hong Kong and Michigan.<\/jats:p>\n                  <jats:p>Adam S. Lauring holds the position of Deputy Editor for JID and has not peer reviewed or made any editorial decisions for this paper.<\/jats:p>\n                <\/jats:sec>","DOI":"10.1101\/2025.05.26.25328346","type":"posted-content","created":{"date-parts":[[2025,5,26]],"date-time":"2025-05-26T23:10:16Z","timestamp":1748301016000},"source":"Crossref","is-referenced-by-count":0,"title":["A prospective, comparative cohort analysis of influenza antibody waning in Michigan and Hong Kong during periods of low influenza circulation"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6011-4152","authenticated-orcid":false,"given":"Yanyupei","family":"Yang","sequence":"first","affiliation":[{"name":"Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Smith","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Faith","family":"Ho","sequence":"additional","affiliation":[{"name":"School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rachel","family":"Truscon","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nancy H. L.","family":"Leung","sequence":"additional","affiliation":[{"name":"School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa","family":"Touyon","sequence":"additional","affiliation":[{"name":"Pasteur Research Pole, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amy","family":"Callear","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-7275-9761","authenticated-orcid":false,"given":"Elie-Tino","family":"Godonou","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher N.","family":"Blair","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arnold S.","family":"Monto","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adam S.","family":"Lauring","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6297-7154","authenticated-orcid":false,"given":"Benjamin J.","family":"Cowling","sequence":"additional","affiliation":[{"name":"School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sook-San","family":"Wong","sequence":"additional","affiliation":[{"name":"Pasteur Research Pole, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emily T.","family":"Martin","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Michigan, Ann Arbor, MI, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026102108351222000_2025.05.26.25328346v2.1","doi-asserted-by":"publisher","DOI":"10.1111\/ajt.16381"},{"key":"2026102108351222000_2025.05.26.25328346v2.2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2013182117"},{"key":"2026102108351222000_2025.05.26.25328346v2.3","doi-asserted-by":"publisher","DOI":"10.2807\/1560-7917.ES.2020.25.47.2001847"},{"key":"2026102108351222000_2025.05.26.25328346v2.4","doi-asserted-by":"publisher","DOI":"10.1016\/S2214-109X(22)00358-8"},{"key":"2026102108351222000_2025.05.26.25328346v2.5","doi-asserted-by":"publisher","DOI":"10.3201\/eid2912.230937"},{"key":"2026102108351222000_2025.05.26.25328346v2.6","doi-asserted-by":"publisher","DOI":"10.46234\/ccdcw2023.206"},{"key":"2026102108351222000_2025.05.26.25328346v2.7","doi-asserted-by":"publisher","DOI":"10.1111\/irv.13106"},{"key":"2026102108351222000_2025.05.26.25328346v2.8","doi-asserted-by":"publisher","DOI":"10.1093\/infdis\/jiae423"},{"key":"2026102108351222000_2025.05.26.25328346v2.9","unstructured":"Michigan COVID-19 Tracker. 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