{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T09:27:22Z","timestamp":1785403642434,"version":"3.56.0"},"reference-count":63,"publisher":"AOSIS","issue":"1","license":[{"start":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T00:00:00Z","timestamp":1782432000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>Background:\u00a0Understanding mucosal immune response to Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination, and its correlation to systemic responses could improve vaccine development. There is limited data on mucosal and systemic antibody responses to SARS-CoV-2 infection and vaccination in African populations.\nObjective:\u00a0This study assessed serum and saliva antibody ratios in a cohort of SARS-CoV-2 infected and vaccinated participants followed up for 12 months.\nMethods:\u00a0This longitudinal study comprised of 67 SARS-CoV-2, PCR-confirmed participants who were recruited as part of a COVID-19 Point of Care Study, between January 2021 and September 2022. For this analysis, 254 serum and 214 saliva samples (205 of which were matched), were collected at baseline, 6, 9, and 12 months. Antibodies against Spike (S) and nucleocapsid (N) SARS-CoV-2 were assessed by in-house Luminex assay.\nResults:\u00a0Serum and saliva anti-S IgG from were detected for up to 12 months in majority of participants (93.5% and 90%), regardless of vaccination status. There was a concordance between paired serum and saliva antibody in 80.5% anti-S IgG and 41.7% anti-N IgG of samples. There was a weak but significant correlation between the matched serum and saliva samples (\u03c1\u00a0= 0.42,\u00a0p\u00a0&lt; 0.001 for anti-S and\u00a0\u03c1\u00a0= 0.33,\u00a0p\u00a0&lt; 0.001 for anti-N). Longitudinal analysis in participants who were vaccinated with either the Ad26.COV2 or BNT162b2 COVID-19 vaccine after their baseline visit, serum anti-S IgG significantly increased (p\u00a0= 0.023 and\u00a0p\u00a0= 0.038), compared with unvaccinated participants. Breakthrough infections or reinfections were identified in (35\/62) 56.5% of vaccinated and unvaccinated participants.\nConclusion:\u00a0This study reports the correlation of the anti-S and anti-N IgG responses in serum and saliva following SARS-CoV-2 infection and subsequent vaccination in low-middle income setting. Furthermore, high breakthroughs and reinfection were reported.\nWhat this study adds:\u00a0The study findings are consistent with those from high-income settings, supporting correlation between systemic and mucosal immunity and booster vaccination as a long-term strategy to control SARS-CoV-2.<\/jats:p>","DOI":"10.4102\/ajlm.v15i1.3052","type":"journal-article","created":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T07:25:19Z","timestamp":1782372319000},"update-policy":"https:\/\/doi.org\/10.4102\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Kinetics of anti-SARS-CoV-2 IgG in saliva and serum post infection, and subsequent vaccination in South Africa"],"prefix":"10.4102","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0686-1293","authenticated-orcid":false,"given":"Maemu P.","family":"Gededzha","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/003hsr719","id-type":"ROR","asserted-by":"publisher"}],"name":"Sefako Makgatho Health Sciences University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4885-1202","authenticated-orcid":false,"given":"Mixo","family":"Sibiya","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00znvbk37","id-type":"ROR","asserted-by":"publisher"}],"name":"National Health Laboratory Service"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2090-9572","authenticated-orcid":false,"given":"Celine","family":"Pellaton","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/019whta54","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Lausanne"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3294-4773","authenticated-orcid":false,"given":"Kubashni","family":"Woeber","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3627-3388","authenticated-orcid":false,"given":"Duduzile","family":"Nsibande","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1832-2863","authenticated-orcid":false,"given":"Nobuhle","family":"Mchunu","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9175-2130","authenticated-orcid":false,"given":"Brodie","family":"Daniels","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7554-2934","authenticated-orcid":false,"given":"Terusha","family":"Chetty","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1710-1556","authenticated-orcid":false,"given":"Reshmi","family":"Dassaye","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-1415-0050","authenticated-orcid":false,"given":"Khanya","family":"Mohlabi","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0316-7087","authenticated-orcid":false,"given":"Shameem","family":"Jaumdally","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03p74gp79","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Cape Town"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7709-5341","authenticated-orcid":false,"given":"Keertan","family":"Dheda","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03p74gp79","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Cape Town"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8560-8581","authenticated-orcid":false,"given":"Ruth","family":"Lekalakala","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/017p87168","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Limpopo"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7629-0636","authenticated-orcid":false,"given":"Shabir A.","family":"Madhi","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03rp50x72","id-type":"ROR","asserted-by":"publisher"}],"name":"University of the Witwatersrand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6360-3488","authenticated-orcid":false,"given":"Elizabeth","family":"Mayne","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03p74gp79","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Cape Town"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4649-1477","authenticated-orcid":false,"given":"Glenda","family":"Gray","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5549-6256","authenticated-orcid":false,"given":"Yves","family":"Levy","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05ggc9x40","id-type":"ROR","asserted-by":"publisher"}],"name":"Universit\u00e9 Paris-Est Cr\u00e9teil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9435-0110","authenticated-orcid":false,"given":"Craig","family":"Fenwick","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0511th722","id-type":"ROR","asserted-by":"publisher"}],"name":"H\u00f4pital Albert-Chenevier"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8069-1056","authenticated-orcid":false,"given":"Song","family":"Ding","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04f2nz275","id-type":"ROR","asserted-by":"publisher"}],"name":"Eurovacc Foundation"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8719-4028","authenticated-orcid":false,"given":"Penny L.","family":"Moore","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03rp50x72","id-type":"ROR","asserted-by":"publisher"}],"name":"University of the Witwatersrand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2394-6486","authenticated-orcid":false,"given":"Ameena","family":"Goga","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05q60vz69","id-type":"ROR","asserted-by":"publisher"}],"name":"South African Medical Research Council"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2580","published-online":{"date-parts":[[2026,6,26]]},"reference":[{"key":"ref0","doi-asserted-by":"crossref","unstructured":"Garenne M, Stiegler N. Covid-19 demography in France and South Africa: A comparative study of morbidity and mortality in 2020-2022. PLoS One. 2024;19(2):e0294870. https:\/\/doi.org\/10.1371\/journal.pone.0294870","DOI":"10.1371\/journal.pone.0294870"},{"key":"ref1","doi-asserted-by":"crossref","unstructured":"Hogan AB, Wu SL, Toor J, et al. Long-term vaccination strategies to mitigate the impact of SARS-CoV-2 transmission: A modelling study. PLoS Med. 2023;20(11):e1004195. https:\/\/doi.org\/10.1371\/journal.pmed.1004195","DOI":"10.1371\/journal.pmed.1004195"},{"key":"ref2","doi-asserted-by":"crossref","unstructured":"Gudbjartsson DF, Norddahl GL, Melsted P, et al. Humoral immune response to SARS-CoV-2 in Iceland. N Engl J Med. 2020;383(18):1724\u20131734. https:\/\/doi.org\/10.1056\/NEJMoa2026116","DOI":"10.1056\/NEJMoa2026116"},{"key":"ref3","doi-asserted-by":"crossref","unstructured":"Olafsdottir TA, Bjarnadottir K, Norddahl GL, et al. HLA alleles, disease severity, and age associate with T-cell responses following infection with SARS-CoV-2. Commun Biol. 2022;5(1):914. https:\/\/doi.org\/10.1038\/s42003-022-03893-w","DOI":"10.1038\/s42003-022-03893-w"},{"key":"ref4","doi-asserted-by":"crossref","unstructured":"Pelleau S, Woudenberg T, Rosado J, et al. Kinetics of the severe acute respiratory syndrome coronavirus 2 antibody response and serological estimation of time since infection. J Infect Dis. 2021;224(9):1489\u20131499. https:\/\/doi.org\/10.1093\/infdis\/jiab375","DOI":"10.1093\/infdis\/jiab375"},{"key":"ref5","doi-asserted-by":"crossref","unstructured":"Jacobs JJL. Neutralizing antibodies mediate virus-immune pathology of COVID-19. Med Hypotheses. 2020;143:109884. https:\/\/doi.org\/10.1016\/j.mehy.2020.109884","DOI":"10.1016\/j.mehy.2020.109884"},{"key":"ref6","doi-asserted-by":"crossref","unstructured":"Jarlhelt I, P\u00e9rez-Al\u00f3s L, Bayarri-Olmos R, et al. Distinguishing SARS-CoV-2 infection and vaccine responses up to 18 months post-infection using nucleocapsid protein and receptor-binding domain antibodies. Microbiol Spectr. 2023;11(5):e0179623. https:\/\/doi.org\/10.1128\/spectrum.01796-23","DOI":"10.1128\/spectrum.01796-23"},{"key":"ref7","doi-asserted-by":"crossref","unstructured":"Ebrahim F, Tabal S, Lamami Y, et al. Anti-SARS-CoV-2 IgG Antibodies post-COVID-19 or post-vaccination in Libyan population: Comparison of four vaccines. Vaccines (Basel). 2022;10(12):2002. https:\/\/doi.org\/10.3390\/vaccines10122002","DOI":"10.3390\/vaccines10122002"},{"key":"ref8","doi-asserted-by":"crossref","unstructured":"Iyer AS, Jones FK, Nodoushani A, et al. Persistence and decay of human antibody responses to the receptor binding domain of SARS-CoV-2 spike protein in COVID-19 patients. Sci Immunol. 2020;5(52):eabe0367. https:\/\/doi.org\/10.1126\/sciimmunol.abe036","DOI":"10.1126\/sciimmunol.abe0367"},{"key":"ref9","doi-asserted-by":"crossref","unstructured":"Scozzari G, Costa C, Migliore E, et al. Prevalence, persistence, and factors associated with SARS-CoV-2 IgG seropositivity in a large cohort of healthcare workers in a tertiary care university hospital in Northern Italy. Viruses. 2021;13(6):1064. https:\/\/doi.org\/10.3390\/v13061064","DOI":"10.3390\/v13061064"},{"key":"ref10","doi-asserted-by":"crossref","unstructured":"Khoury DS, Cromer D, Reynaldi A, et al. Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection. Nat Med. 2021;27(7):1205\u20131211. https:\/\/doi.org\/10.1038\/s41591-021-01377-8","DOI":"10.1038\/s41591-021-01377-8"},{"key":"ref11","doi-asserted-by":"crossref","unstructured":"Regev-Yochay G, Lustig Y, Joseph G, et al. Correlates of protection against COVID-19 infection and intensity of symptomatic disease in vaccinated individuals exposed to SARS-CoV-2 in households in Israel (ICoFS): a prospective cohort study. Lancet Microbe. 2023;4(5):e309\u2013e318. https:\/\/doi.org\/10.1016\/S2666-5247(23)00012-5","DOI":"10.1016\/S2666-5247(23)00012-5"},{"key":"ref12","doi-asserted-by":"crossref","unstructured":"Sun K, Bhiman JN, Tempia S, et al. SARS-CoV-2 correlates of protection from infection against variants of concern. Nat Med. 2024;30(10):2805\u20132812. https:\/\/doi.org\/10.1038\/s41591-024-03131-2","DOI":"10.1038\/s41591-024-03131-2"},{"key":"ref13","doi-asserted-by":"crossref","unstructured":"Jacobsen H, Sitaras I, Katzmarzyk M, et al. Systematic review and meta-analysis of the factors affecting waning of post-vaccination neutralizing antibody responses against SARS-CoV-2. NPJ Vaccines. 2023;8(1):159. https:\/\/doi.org\/10.1038\/s41541-023-00756-1","DOI":"10.1038\/s41541-023-00756-1"},{"key":"ref14","doi-asserted-by":"crossref","unstructured":"Li H, Wang Y, Ji M, et al. Transmission routes analysis of SARS-CoV-2: A systematic review and case report. Front Cell Dev Biol. 2020;8:618. https:\/\/doi.org\/10.3389\/fcell.2020.00618","DOI":"10.3389\/fcell.2020.00618"},{"key":"ref15","doi-asserted-by":"crossref","unstructured":"Butler SE, Crowley AR, Natarajan H, et al. Distinct features and functions of systemic and mucosal humoral immunity among SARS-CoV-2 convalescent individuals. Front Immunol. 2020;11:618685. https:\/\/doi.org\/10.3389\/fimmu.2020.618685","DOI":"10.3389\/fimmu.2020.618685"},{"key":"ref16","doi-asserted-by":"crossref","unstructured":"Alkharaan H, Bayati S, Hellstrom C, et al. Persisting salivary IgG Against SARS-CoV-2 at 9 months after mild COVID-19: A complementary approach to population surveys. J Infect Dis. 2021;224(3):407\u2013414. https:\/\/doi.org\/10.1093\/infdis\/jiab256","DOI":"10.1093\/infdis\/jiab256"},{"key":"ref17","doi-asserted-by":"crossref","unstructured":"Egorov AI, Griffin SM, Fuzawa M, et al. A multiplex noninvasive salivary antibody assay for SARS-CoV-2 infection and its application in a population-based survey by mail. Microbiol Spectr. 2021;9(2):e0069321. https:\/\/doi.org\/10.1128\/Spectrum.00693-21","DOI":"10.1128\/Spectrum.00693-21"},{"key":"ref18","doi-asserted-by":"crossref","unstructured":"Wright PF, Prevost-Reilly AC, Natarajan H, et al. Longitudinal systemic and mucosal immune responses to SARS-CoV-2 infection. J Infect Dis. 2022;226(7):1204\u20131214. https:\/\/doi.org\/10.1093\/infdis\/jiac065","DOI":"10.1093\/infdis\/jiac065"},{"key":"ref19","doi-asserted-by":"crossref","unstructured":"Chan RWY, Liu S, Cheung JY, et al. The mucosal and serological immune responses to the novel coronavirus (SARS-CoV-2) vaccines. Front Immunol. 2021;12:744887. https:\/\/doi.org\/10.3389\/fimmu.2021.744887","DOI":"10.3389\/fimmu.2021.744887"},{"key":"ref20","doi-asserted-by":"crossref","unstructured":"Puhach O, Bellon M, Adea K, et al. SARS-CoV-2 convalescence and hybrid immunity elicits mucosal immune responses. EBioMedicine. 2023;98:104893. https:\/\/doi.org\/10.1016\/j.ebiom.2023.104893","DOI":"10.1016\/j.ebiom.2023.104893"},{"key":"ref21","doi-asserted-by":"crossref","unstructured":"Mitsi E, Diniz MO, Reine J, et al. Respiratory mucosal immune memory to SARS-CoV-2 after infection and vaccination. Nat Commun. 2023;14(1):6815. https:\/\/doi.org\/10.1038\/s41467-023-42433-w","DOI":"10.1038\/s41467-023-42433-w"},{"key":"ref22","doi-asserted-by":"crossref","unstructured":"Faustini SE, Cook A, Hill H, et al. Saliva antiviral antibody levels are detectable but correlate poorly with serum antibody levels following SARS-CoV-2 infection and\/or vaccination. J Infect. 2023;87(4):328\u2013335. https:\/\/doi.org\/10.1016\/j.jinf.2023.07.018","DOI":"10.1016\/j.jinf.2023.07.018"},{"key":"ref23","doi-asserted-by":"crossref","unstructured":"Chellamuthu P, Angel AN, MacMullan MA, et al. SARS-CoV-2 specific IgG antibodies persist over a 12-month period in oral mucosal fluid collected from previously infected individuals. Front Immunol. 2021;12:777858. https:\/\/doi.org\/10.3389\/fimmu.2021.777858","DOI":"10.3389\/fimmu.2021.777858"},{"key":"ref24","doi-asserted-by":"crossref","unstructured":"Pinilla YT, Heinzel C, Caminada LF, et al. SARS-CoV-2 antibodies are persisting in saliva for more than 15 months after infection and become strongly boosted after vaccination. Front Immunol. 2021;12:798859. https:\/\/doi.org\/10.3389\/fimmu.2021.798859","DOI":"10.3389\/fimmu.2021.798859"},{"key":"ref25","doi-asserted-by":"crossref","unstructured":"Anggraeni R, Ana ID, Wihadmadyatami H. Development of mucosal vaccine delivery: An overview on the mucosal vaccines and their adjuvants. Clin Exp Vaccine Res. 2022;11(3):235\u2013248. https:\/\/doi.org\/10.7774\/cevr.2022.11.3.235","DOI":"10.7774\/cevr.2022.11.3.235"},{"key":"ref26","unstructured":"Goga A, Mayne ES, Woeber K, et al. Point-of-care antibody tests for COVID-19: Field-based performance, South Africa. In Special Issue: Abstracts From the 2022 Conference on Retroviruses and Opportunistic Infections_Abstract823-4 (1). Top Antiv Med [serial online]. 2022 [cited 2025 Feb 25];30(1):331. Available from: https:\/\/www.researchgate.net\/publication\/361164561_point_of_care_antibody_tests_during_covid-19_field-based_performance_south_africa"},{"key":"ref27","unstructured":"Goga A, Mayne ES, Woeber K, et al. Utility of Covid-19 point of care antigen tests in low-middle income settings. Top Antiv Med. 2022;30(11):331. https:\/\/hdl.handle.net\/11288\/598210"},{"key":"ref28","doi-asserted-by":"crossref","unstructured":"Fenwick C, Croxatto A, Coste AT, et al. Changes in SARS-CoV-2 Spike versus nucleoprotein antibody responses impact the estimates of infections in population-based seroprevalence studies. J Virol. 2021;95(3):e01828-20. https:\/\/doi.org\/10.1128\/JVI.01828-20","DOI":"10.1128\/JVI.01828-20"},{"key":"ref29","unstructured":"WHO. Clinical management of COVID-19: Living guidance [homepage on the Internet]. World Health Organization; 2021 [cited 2025 Sep 10]. Available from: https:\/\/www.who.int\/publications\/i\/item\/B09467"},{"key":"ref30","doi-asserted-by":"crossref","unstructured":"Zhang Z, Hong W, Zhang Y, Li X, Que H, Wei X. Mucosal immunity and vaccination strategies: Current insights and future perspectives. Mol Biomed. 2025;6(1):57. https:\/\/doi.org\/10.1186\/s43556-025-00301-7","DOI":"10.1186\/s43556-025-00301-7"},{"key":"ref31","doi-asserted-by":"crossref","unstructured":"Madhi SA, Kwatra G, Myers JE, et al. Population immunity and Covid-19 severity with Omicron variant in South Africa. N Engl J Med. 2022;386(14):1314\u20131326. https:\/\/doi.org\/10.1056\/NEJMoa2119658","DOI":"10.1056\/NEJMoa2119658"},{"key":"ref32","doi-asserted-by":"crossref","unstructured":"Heaney CD, Pisanic N, Randad PR, et al. Comparative performance of multiplex salivary and commercially available serologic assays to detect SARS-CoV-2 IgG and neutralization titers. J Clin Virol. 2021;145:104997. https:\/\/doi.org\/10.1016\/j.jcv.2021.104997","DOI":"10.1016\/j.jcv.2021.104997"},{"key":"ref33","doi-asserted-by":"crossref","unstructured":"Li D, Calderone R, Nsouli TM, Reznikov E, Bellanti JA. Salivary and serum IgA and IgG responses to SARS-CoV-2-spike protein following SARS-CoV-2 infection and after immunization with COVID-19 vaccines. Allergy Asthma Proc. 2022;43(5):419\u2013430. https:\/\/doi.org\/10.2500\/aap.2022.43.220045","DOI":"10.2500\/aap.2022.43.220045"},{"key":"ref34","doi-asserted-by":"crossref","unstructured":"Cohen JI, Dropulic L, Wang K, et al. Comparison of levels of nasal, salivary, and plasma antibody to severe acute respiratory syndrome coronavirus 2 during natural infection and after vaccination. Clin Infect Dis. 2023;76(8):1391\u20131399. https:\/\/doi.org\/10.1093\/cid\/ciac934","DOI":"10.1093\/cid\/ciac934"},{"key":"ref35","doi-asserted-by":"crossref","unstructured":"Klingler J, Lambert GS, Itri V, et al. Detection of antibody responses against SARS-CoV-2 in plasma and saliva from vaccinated and infected individuals. Front Immunol. 2021;12:759688. https:\/\/doi.org\/10.3389\/fimmu.2021.759688","DOI":"10.3389\/fimmu.2021.759688"},{"key":"ref36","doi-asserted-by":"crossref","unstructured":"Bolotin S, Tran V, Osman S, et al. SARS-CoV-2 seroprevalence survey estimates are affected by anti-nucleocapsid antibody decline. J Infect Dis. 2021;223(8):1334\u20131338. https:\/\/doi.org\/10.1093\/infdis\/jiaa796","DOI":"10.1093\/infdis\/jiaa796"},{"key":"ref37","doi-asserted-by":"crossref","unstructured":"Van Elslande J, Oyaert M, Lorent N, et al. Lower persistence of anti-nucleocapsid compared to anti-spike antibodies up to one year after SARS-CoV-2 infection. Diagn Microbiol Infect Dis. 2022;103(1):115659. https:\/\/doi.org\/10.1016\/j.diagmicrobio.2022.115659","DOI":"10.1016\/j.diagmicrobio.2022.115659"},{"key":"ref38","doi-asserted-by":"crossref","unstructured":"Guerra ENS, De Castro VT, Amorim Dos Santos J, Acevedo AC, Chardin H. Saliva is suitable for SARS-CoV-2 antibodies detection after vaccination: A rapid systematic review. Front Immunol. 2022;13:1006040. https:\/\/doi.org\/10.3389\/fimmu.2022.1006040","DOI":"10.3389\/fimmu.2022.1006040"},{"key":"ref39","doi-asserted-by":"crossref","unstructured":"Movsisyan M, Truzyan N, Kasparova I, et al. Tracking the evolution of anti-SARS-CoV-2 antibodies and long-term humoral immunity within 2 years after COVID-19 infection. Sci Rep. 2024;14(1):13417. https:\/\/doi.org\/10.1038\/s41598-024-64414-9","DOI":"10.1038\/s41598-024-64414-9"},{"key":"ref40","doi-asserted-by":"crossref","unstructured":"Batra M, Tian R, Zhang C, et al. Role of IgG against N-protein of SARS-CoV2 in COVID19 clinical outcomes. Sci Rep. 2021;11(1):3455. https:\/\/doi.org\/10.1038\/s41598-021-83108-0","DOI":"10.1038\/s41598-021-83108-0"},{"key":"ref41","doi-asserted-by":"crossref","unstructured":"Gray G, Collie S, Goga A, et al. Effectiveness of Ad26.COV2.S and BNT162b2 vaccines against omicron variant in South Africa. N Engl J Med. 2022;386:2243\u20132245. https:\/\/doi.org\/10.1056\/NEJMc2202061","DOI":"10.1056\/NEJMc2202061"},{"key":"ref42","doi-asserted-by":"crossref","unstructured":"Sadoff J, Gray G, Vandebosch A, et al. Safety and efficacy of single-dose Ad26.COV2.S vaccine against Covid-19. N Engl J Med. 2021;384(23):2187\u20132201. https:\/\/doi.org\/10.1056\/NEJMoa2101544","DOI":"10.1056\/NEJMoa2101544"},{"key":"ref43","doi-asserted-by":"crossref","unstructured":"O\u2019Shea KM, Schuler CF, Chen J, et al. Wild-type SARS-CoV-2 neutralizing immunity decreases across variants and over time but correlates well with diagnostic testing. Front Immunol. 2023;14:1055429. https:\/\/doi.org\/10.3389\/fimmu.2023.1055429","DOI":"10.3389\/fimmu.2023.1055429"},{"key":"ref44","doi-asserted-by":"crossref","unstructured":"Paul MJ, Hudda MT, Pallett S, et al. Mucosal immune responses to SARS-CoV-2 infection and COVID-19 vaccination. Vaccine. 2025;56:127175. https:\/\/doi.org\/10.1016\/j.vaccine.2025.127175","DOI":"10.1016\/j.vaccine.2025.127175"},{"key":"ref45","doi-asserted-by":"crossref","unstructured":"Gorochov G, Ropers J, Launay O, et al. Serum and salivary IgG and IgA response after COVID-19 messenger RNA vaccination. JAMA Netw Open. 2024;7(4):e248051. https:\/\/doi.org\/10.1001\/jamanetworkopen.2024.8051","DOI":"10.1001\/jamanetworkopen.2024.8051"},{"key":"ref46","doi-asserted-by":"crossref","unstructured":"Keeton R, Richardson SI, Moyo-Gwete T, et al. Prior infection with SARS-CoV-2 boosts and broadens Ad26.COV2.S immunogenicity in a variant-dependent manner. Cell Host Microbe. 2021;29(11):1611.e5\u20131619.e5. https:\/\/doi.org\/10.1016\/j.chom.2021.10.003","DOI":"10.1016\/j.chom.2021.10.003"},{"key":"ref47","doi-asserted-by":"crossref","unstructured":"Ketas TJ, Chaturbhuj D, Portillo VMC, et al. Antibody responses to SARS-CoV-2 mRNA vaccines are detectable in saliva. Pathog Immun. 2021;6(1):116\u2013134. https:\/\/doi.org\/10.20411\/pai.v6i1.441","DOI":"10.20411\/pai.v6i1.441"},{"key":"ref48","doi-asserted-by":"crossref","unstructured":"Nguyen K, Relja B, Epperson M, et al. Salivary immune responses after COVID-19 vaccination. PLoS One. 2024;19(9):e0307936. https:\/\/doi.org\/10.1371\/journal.pone.0307936","DOI":"10.1371\/journal.pone.0307936"},{"key":"ref49","doi-asserted-by":"crossref","unstructured":"Azzi L, Dalla Gasperina D, Veronesi G, et al. Mucosal immune response in BNT162b2 COVID-19 vaccine recipients. EBioMedicine. 2022;75:103788. https:\/\/doi.org\/10.1016\/j.ebiom.2021.103788","DOI":"10.1016\/j.ebiom.2021.103788"},{"key":"ref50","doi-asserted-by":"crossref","unstructured":"Islam MA. A review of SARS-CoV-2 variants and vaccines: Viral properties, mutations, vaccine efficacy, and safety. Infect Med (Beijing). 2023;2(4):247\u2013261. https:\/\/doi.org\/10.1016\/j.imj.2023.08.005","DOI":"10.1016\/j.imj.2023.08.005"},{"key":"ref51","doi-asserted-by":"crossref","unstructured":"Gaeta A, Angeloni A, Napoli A, et al. Anti-N SARS-CoV-2 assays for evaluation of natural viral infection. J Immunol Methods. 2023;518:113486. https:\/\/doi.org\/10.1016\/j.jim.2023.113486","DOI":"10.1016\/j.jim.2023.113486"},{"key":"ref52","doi-asserted-by":"crossref","unstructured":"Hussain A, Sarfaraz S, Anis S, et al. Breakthrough COVID-19 infections \u2013 Analyzing our experience. Pak J Med Sci. 2023;39(5):1225\u20131231. https:\/\/doi.org\/10.12669\/pjms.39.5.6724","DOI":"10.12669\/pjms.39.5.6724"},{"key":"ref53","doi-asserted-by":"crossref","unstructured":"Serwanga J, Kato L, Oluka GK, et al. The single-dose Janssen Ad26.COV2.S COVID-19 vaccine elicited robust and persistent anti-spike IgG antibody responses in a 12-month Ugandan cohort. Front Immunol. 2024;15:1384668. https:\/\/doi.org\/10.3389\/fimmu.2024.1384668","DOI":"10.3389\/fimmu.2024.1384668"},{"key":"ref54","doi-asserted-by":"crossref","unstructured":"Vivaldi G, Jolliffe DA, Faustini S, et al. Correlation between postvaccination anti-spike antibody titers and protection against breakthrough severe acute respiratory syndrome coronavirus 2 infection: A population-based longitudinal study. J Infect Dis. 2022;226(11):1903\u20131908. https:\/\/doi.org\/10.1093\/infdis\/jiac321","DOI":"10.1093\/infdis\/jiac321"},{"key":"ref55","doi-asserted-by":"crossref","unstructured":"Aldridge RW, Yavlinsky A, Nguyen V, et al. SARS-CoV-2 antibodies and breakthrough infections in the Virus Watch cohort. Nat Commun. 2022;13(1):4869. https:\/\/doi.org\/10.1038\/s41467-022-32265-5","DOI":"10.1038\/s41467-022-32265-5"},{"key":"ref56","doi-asserted-by":"crossref","unstructured":"Martin Perez C, Aguilar R, Jimenez A, et al. Correlates of protection and determinants of SARS-CoV-2 breakthrough infections 1 year after third dose vaccination. BMC Med. 2024;22(1):103. https:\/\/doi.org\/10.1186\/s12916-024-03304-3","DOI":"10.1186\/s12916-024-03304-3"},{"key":"ref57","doi-asserted-by":"crossref","unstructured":"Sanghavi DK, Bhakta S, Wadei HM, et al. Low antispike antibody levels correlate with poor outcomes in COVID-19 breakthrough hospitalizations. J Intern Med. 2022;292(1):127\u2013135. https:\/\/doi.org\/10.1111\/joim.13471","DOI":"10.1111\/joim.13471"},{"key":"ref58","doi-asserted-by":"crossref","unstructured":"Al Hasan SM, Saulam J, Mikami F, Kanda K, Yokoi H, Hirao T. COVID-19 outbreak trends in South Africa: A comparison of Omicron (B.1.1.529), Delta (B.1.617.2), and Beta (B.1.351) variants outbreak periods. J Infect Public Health. 2022;15(7):726\u2013733. https:\/\/doi.org\/10.1016\/j.jiph.2022.05.011","DOI":"10.1016\/j.jiph.2022.05.011"},{"key":"ref59","doi-asserted-by":"crossref","unstructured":"Goga A, Bekker LG, Garrett N, et al. Breakthrough SARS-CoV-2 infections during periods of delta and omicron predominance, South Africa. Lancet. 2022;400(10348):269\u2013271. https:\/\/doi.org\/10.1016\/S0140-6736(22)01190-4","DOI":"10.1016\/S0140-6736(22)01190-4"},{"key":"ref60","doi-asserted-by":"crossref","unstructured":"Nunes MC, Mbotwe-Sibanda S, Baillie VL, et al. SARS-CoV-2 Omicron symptomatic infections in previously infected or vaccinated South African healthcare workers. Vaccines (Basel). 2022;10(3):459. https:\/\/doi.org\/10.3390\/vaccines10030459","DOI":"10.3390\/vaccines10030459"},{"key":"ref61","doi-asserted-by":"crossref","unstructured":"Moreira ED, Jr, Kitchin N, Xu X, et al. Safety and efficacy of a third dose of BNT162b2 Covid-19 vaccine. N Engl J Med. 2022;386(20):1910\u20131921. https:\/\/doi.org\/10.1056\/NEJMoa2200674","DOI":"10.1056\/NEJMoa2200674"},{"key":"ref62","doi-asserted-by":"crossref","unstructured":"Kitchin D, Richardson SI, van der Mescht MA, et al. Ad26.COV2.S breakthrough infections induce high titers of neutralizing antibodies against Omicron and other SARS-CoV-2 variants of concern. Cell Rep Med. 2022;3:100535. https:\/\/doi.org\/10.1016\/j.xcrm.2022.100535","DOI":"10.1016\/j.xcrm.2022.100535"}],"container-title":["African Journal of Laboratory Medicine"],"original-title":[],"link":[{"URL":"https:\/\/ajlmonline.org\/index.php\/ajlm\/article\/view\/3052\/3499","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T07:28:09Z","timestamp":1782372489000},"score":1,"resource":{"primary":{"URL":"https:\/\/ajlmonline.org\/index.php\/ajlm\/article\/view\/3052"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,26]]},"references-count":63,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1,1]]}},"URL":"https:\/\/doi.org\/10.4102\/ajlm.v15i1.3052","relation":{},"ISSN":["2225-2002","2225-2010"],"issn-type":[{"value":"2225-2002","type":"print"},{"value":"2225-2010","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,26]]},"article-number":"a3052"}}