{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T09:12:45Z","timestamp":1790327565237,"version":"4.1.0"},"reference-count":33,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T00:00:00Z","timestamp":1790294400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T00:00:00Z","timestamp":1790294400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vox Sanguinis"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background and Objectives<\/jats:title>\n                    <jats:p>A cohort of South African repeat blood donors was established to leverage the repeated presentation of blood donors for longitudinal serological surveillance of severe acute respiratory syndrome coronavirus 2 (SARS\u2010CoV\u20102) infections and reinfection incidence in a highly exposed population.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and Methods<\/jats:title>\n                    <jats:p>The prospective cohort was followed from January 2022 to December 2023, with a total of 7459 blood samples from 2155 donors captured and tested using the Roche anti\u2010nucleocapsid (N) and anti\u2010spike (S) total immunoglobulin antibody (Ab) assays. First infections were identified by anti\u2010N seroconversion and reinfections by anti\u2010N boosting (\u22651.5\u2010fold) in longitudinal testing, using a novel method to reduce misclassification from prolonged Ab maturation. Incidence was estimated, and correlates of infection were assessed using multivariable Cox proportional hazards regression.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A total of 948 infection events were observed during the study period\u2014280 first infections and 668 reinfections, with up to 4 serial infection events in one donor. Total infection incidence was estimated at 64.2 infections\/100 person\u2010years (95% confidence interval [CI]: 60.2\u201368.4). In multivariable models, quartile of anti\u2010N reactivity was a strong correlate of protection against reinfection with an adjusted hazard ratio of 0.26 (95% CI: 0.18\u20130.38).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Longitudinal blood donor serosurveillance allowed quantification of continuing SARS\u2010CoV\u20102 transmission after most individuals had been previously infected in the 2\u2009years after relaxation of non\u2010pharmaceutical interventions.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1111\/vox.70368","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T08:57:39Z","timestamp":1790326659000},"source":"Crossref","is-referenced-by-count":0,"title":["Rates of severe acute respiratory syndrome coronavirus 2 infection in a highly exposed South African blood donor cohort, 2022\u20132023"],"prefix":"10.1111","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4383-4526","authenticated-orcid":false,"given":"Marion","family":"Vermeulen","sequence":"first","affiliation":[{"name":"South African National Blood Service  Johannesburg South Africa"},{"name":"Department of Internal Medicine University of the Free State  Bloemfontein South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ronel","family":"Swanevelder","sequence":"additional","affiliation":[{"name":"South African National Blood Service  Johannesburg South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cordelia","family":"Mmenu","sequence":"additional","affiliation":[{"name":"South African National Blood Service  Johannesburg South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tinus","family":"Brits","sequence":"additional","affiliation":[{"name":"South African National Blood Service  Johannesburg South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Josephine","family":"Mitchel","sequence":"additional","affiliation":[{"name":"South African National Blood Service  Johannesburg South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7046-7245","authenticated-orcid":false,"given":"Eduard","family":"Grebe","sequence":"additional","affiliation":[{"name":"Eduard Grebe Consulting  Cape Town South Africa"},{"name":"Vitalant Research Institute  San Francisco California USA"},{"name":"Division of Epidemiology and Biostatistics, School of Public Health University of Cape Town  Cape Town South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,25]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1016\/S1473-3099(22)00069-X","article-title":"SARS\u2010CoV\u20102 incidence, transmission, and reinfection in a rural and an urban setting: results of the PHIRST\u2010C cohort study, South Africa, 2020\u201321","volume":"22","author":"Cohen C","year":"2022","journal-title":"Lancet Infect Dis"},{"key":"e_1_2_9_3_1","doi-asserted-by":"crossref","first-page":"242","DOI":"10.1111\/vox.13571","article-title":"The evolution and interpretation of seroprevalence of SARS\u2010CoV\u20102 antibodies among South African blood donors from the Beta to Omicron variant\u2010driven waves","volume":"119","author":"Vermeulen M","year":"2024","journal-title":"Vox Sang"},{"key":"e_1_2_9_4_1","doi-asserted-by":"crossref","DOI":"10.1126\/science.abn4947","article-title":"Increased risk of SARS\u2010CoV\u20102 reinfection associated with emergence of Omicron in South Africa","volume":"376","author":"Pulliam JRC","year":"2022","journal-title":"Science"},{"key":"e_1_2_9_5_1","first-page":"31","article-title":"Test\u2010Trace strategy for disease control and management: South Africa's control measures to contain the spread of COVID\u201019","volume":"24","author":"Modisenyane M","year":"2023","journal-title":"S Afr Health Rev"},{"key":"e_1_2_9_6_1","doi-asserted-by":"crossref","DOI":"10.3390\/vaccines12060628","article-title":"COVID\u201019 vaccine uptake and effectiveness by time since vaccination in the Western Cape Province, South Africa: an observational cohort study during 2020\u20132022","volume":"12","author":"Kassanjee R","year":"2024","journal-title":"Vaccines"},{"key":"e_1_2_9_7_1","doi-asserted-by":"crossref","DOI":"10.1126\/scitranslmed.abo7081","article-title":"SARS\u2010CoV\u20102 transmission, persistence of immunity, and estimates of Omicron's impact in South African population cohorts","volume":"14","author":"Sun K","year":"2022","journal-title":"Sci Transl Med"},{"key":"e_1_2_9_8_1","doi-asserted-by":"crossref","DOI":"10.1038\/s41467-022-35652-0","article-title":"Rapidly shifting immunologic landscape and severity of SARS\u2010CoV\u20102 in the Omicron era in South Africa","volume":"14","author":"Sun K","year":"2023","journal-title":"Nat Commun"},{"key":"e_1_2_9_9_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.lanepe.2022.100479","article-title":"Seroprevalence and infection fatality rate of the SARS\u2010CoV\u20102 Omicron variant in Denmark: a nationwide serosurveillance study","volume":"21","author":"Erikstrup C","year":"2022","journal-title":"Lancet Reg Health Eur"},{"key":"e_1_2_9_10_1","doi-asserted-by":"crossref","first-page":"1400","DOI":"10.1001\/jama.2021.15161","article-title":"Estimated US infection\u2010 and vaccine\u2010induced SARS\u2010CoV\u20102 seroprevalence based on blood donations, July 2020\u2013May 2021","volume":"326","author":"Jones JM","year":"2021","journal-title":"JAMA"},{"key":"e_1_2_9_11_1","doi-asserted-by":"crossref","first-page":"298","DOI":"10.1001\/jama.2022.9745","article-title":"Updated US infection\u2010 and vaccine\u2010induced SARS\u2010CoV\u20102 seroprevalence estimates based on blood donations, July 2020\u2013December 2021","volume":"328","author":"Jones JM","year":"2022","journal-title":"JAMA"},{"key":"e_1_2_9_12_1","doi-asserted-by":"crossref","first-page":"601","DOI":"10.15585\/mmwr.mm7222a3","article-title":"Estimates of SARS\u2010CoV\u20102 seroprevalence and incidence of primary SARS\u2010CoV\u20102 infections among blood donors, by COVID\u201019 vaccination status\u2014United States, April 2021\u2013September 2022","volume":"72","author":"Jones JM","year":"2023","journal-title":"MMWR Morb Mortal Wkly Rep"},{"key":"e_1_2_9_13_1","doi-asserted-by":"crossref","DOI":"10.1186\/s12879-022-07094-y","article-title":"Reinfection by the SARS\u2010CoV\u20102 Gamma variant in blood donors in Manaus, Brazil","volume":"22","author":"Prete CA","year":"2022","journal-title":"BMC Infect Dis"},{"key":"e_1_2_9_14_1","doi-asserted-by":"crossref","first-page":"958","DOI":"10.3201\/eid3105.250021","article-title":"Detection of SARS\u2010CoV\u20102 reinfections using nucleocapsid antibody boosting","volume":"31","author":"Grebe E","year":"2025","journal-title":"Emerg Infect Dis"},{"key":"e_1_2_9_15_1","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0082224","article-title":"A panel of ancestry informative markers for the complex five\u2010way admixed South African coloured population","volume":"8","author":"Daya M","year":"2013","journal-title":"PLoS One"},{"key":"e_1_2_9_16_1","doi-asserted-by":"crossref","DOI":"10.1128\/spectrum.03234-22","article-title":"Evaluation of Ortho VITROS and Roche Elecsys S and NC immunoassays for SARS\u2010CoV\u20102 serosurveillance applications","volume":"11","author":"Sulaeman H","year":"2023","journal-title":"Microbiol Spectr"},{"key":"e_1_2_9_17_1","unstructured":"ZaaijerH HogemaB.Exploration of outbreaks in the Netherlands by Sanquin Blood Supply Foundation. National serosurveillance efforts across the globe2024."},{"key":"e_1_2_9_18_1","doi-asserted-by":"crossref","first-page":"195","DOI":"10.3390\/diagnostics16020195","article-title":"Reinfection\u2010driven accumulation of SARS\u2010CoV\u20102 antibodies: a 36\u2010month longitudinal study in Austrian blood donors","volume":"16","author":"Kartal O","year":"2026","journal-title":"Diagnostics"},{"key":"e_1_2_9_19_1","doi-asserted-by":"crossref","DOI":"10.3389\/fpubh.2024.1353415","article-title":"Protective effectiveness of previous infection against subsequent SARS\u2010Cov\u20102 infection: systematic review and meta\u2010analysis","volume":"12","author":"Hu W\u2010H","year":"2024","journal-title":"Front Public Health"},{"key":"e_1_2_9_20_1","doi-asserted-by":"crossref","DOI":"10.1136\/bmjresp-2024-002718","article-title":"Protection conferred by SARS\u2010CoV\u20102 infection across a spectrum of reinfection symptoms and severities","volume":"12","author":"Sukik L","year":"2025","journal-title":"BMJ Open Respir Res"},{"key":"e_1_2_9_21_1","unstructured":"Government of South Africa.Transitional measures.2022. Available from:https:\/\/www.gov.za\/covid-19\/about\/transitional. Last accessed 17 Mar 2026."},{"key":"e_1_2_9_22_1","doi-asserted-by":"crossref","DOI":"10.7196\/SAMJ.2024.v114i3.702","article-title":"Determination of anti\u2010COVID\u201019 IgG and IgM seroprevalence among pregnant women at Pietersburg Hospital, Limpopo Province, South Africa","volume":"114","author":"Rukasha I","year":"2024","journal-title":"S Afr Med J"},{"key":"e_1_2_9_23_1","unstructured":"NICD.Weekly hospital surveillance (DATCOV) update. NICD. 2022. Available from:https:\/\/www.nicd.ac.za\/diseases-a-z-index\/disease-index-covid-19\/surveillance-reports\/weekly-hospital-surveillance-datcov-update\/. Last accessed 23 Aug 2026."},{"key":"e_1_2_9_24_1","doi-asserted-by":"crossref","first-page":"2032","DOI":"10.1038\/s41591-021-01540-1","article-title":"Correlates of protection against symptomatic and asymptomatic SARS\u2010CoV\u20102 infection","volume":"27","author":"Feng S","year":"2021","journal-title":"Nat Med"},{"key":"e_1_2_9_25_1","doi-asserted-by":"crossref","first-page":"1072","DOI":"10.1038\/s41591-022-01721-6","article-title":"Antibody responses and correlates of protection in the general population after two doses of the ChAdOx1 or BNT162b2 vaccines","volume":"28","author":"Wei J","year":"2022","journal-title":"Nat Med"},{"key":"e_1_2_9_26_1","doi-asserted-by":"crossref","first-page":"2805","DOI":"10.1038\/s41591-024-03131-2","article-title":"SARS\u2010CoV\u20102 correlates of protection from infection against variants of concern","volume":"30","author":"Sun K","year":"2024","journal-title":"Nat Med"},{"key":"e_1_2_9_27_1","doi-asserted-by":"crossref","first-page":"1302","DOI":"10.1093\/infdis\/jiaf329","article-title":"Estimated US trends in SARS\u2010CoV\u20102 spike antibody concentrations and correlation to risk of first\u2010time infections based on blood donations, 2022","volume":"232","author":"Jones J","year":"2025","journal-title":"J Infect Dis"},{"key":"e_1_2_9_28_1","doi-asserted-by":"crossref","first-page":"2677","DOI":"10.1111\/trf.16555","article-title":"SARS\u2010CoV\u20102 antibody persistence in COVID\u201019 convalescent plasma donors: dependency on assay format and applicability to serosurveillance","volume":"61","author":"Di Germanio C","year":"2021","journal-title":"Transfusion"},{"key":"e_1_2_9_29_1","doi-asserted-by":"crossref","first-page":"2063","DOI":"10.1111\/trf.18017","article-title":"Spike and nucleocapsid antibody dynamics following SARS\u2010CoV\u20102 infection and vaccination: implications for sourcing COVID\u201019 convalescent plasma from routinely collected blood donations","volume":"64","author":"Di Germanio C","year":"2024","journal-title":"Transfusion"},{"key":"e_1_2_9_30_1","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1111\/trf.17190","article-title":"The healthy donor effect and survey participation, becoming a donor and donor career","volume":"63","author":"Brodersen T","year":"2023","journal-title":"Transfusion"},{"key":"e_1_2_9_31_1","doi-asserted-by":"crossref","first-page":"2221","DOI":"10.1111\/j.1537-2995.2009.02271.x","article-title":"Minority and foreign\u2010born representation among US blood donors: demographics and donation frequency for 2006","volume":"49","author":"Murphy EL","year":"2009","journal-title":"Transfusion"},{"key":"e_1_2_9_32_1","doi-asserted-by":"crossref","first-page":"330","DOI":"10.1111\/hsc.12650","article-title":"Comparison of the demographic and social profile of blood donors and nondonors in Brazil","volume":"27","author":"Zucoloto ML","year":"2019","journal-title":"Health Soc Care Community"},{"key":"e_1_2_9_33_1","doi-asserted-by":"crossref","first-page":"535","DOI":"10.1177\/13634593211017962","article-title":"\u201cMissing minorities\u201d in blood donation: rethinking blood procurement in Europe as a citizenship regime","volume":"25","author":"Wittock N","year":"2021","journal-title":"Health"},{"key":"e_1_2_9_34_1","doi-asserted-by":"crossref","DOI":"10.1016\/j.jvacx.2024.100498","article-title":"SARS\u2010CoV\u20102 vaccination in Canadian blood donors: insight into donor representativeness of the general population","volume":"18","author":"O'Brien SF","year":"2024","journal-title":"Vaccine X"}],"container-title":["Vox Sanguinis"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/vox.70368","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/vox.70368","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/vox.70368","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T08:57:43Z","timestamp":1790326663000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/vox.70368"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,25]]},"references-count":33,"alternative-id":["10.1111\/vox.70368"],"URL":"https:\/\/doi.org\/10.1111\/vox.70368","archive":["Portico"],"relation":{},"ISSN":["0042-9007","1423-0410"],"issn-type":[{"value":"0042-9007","type":"print"},{"value":"1423-0410","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,25]]},"article-number":"vox.70368"}}