{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T18:23:00Z","timestamp":1785435780698,"version":"3.56.0"},"reference-count":29,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T00:00:00Z","timestamp":1779235200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Science, Technological Development, and Innovation of the Republic of Serbia","award":["451-03-136\/2026-03\/200168"],"award-info":[{"award-number":["451-03-136\/2026-03\/200168"]}]},{"name":"Ministry of Science, Technological Development, and Innovation of the Republic of Serbia","award":["451-03-33\/2026-03\/200007"],"award-info":[{"award-number":["451-03-33\/2026-03\/200007"]}]},{"award":["451-03-136\/2026-03\/200168"],"award-info":[{"award-number":["451-03-136\/2026-03\/200168"]}],"id":[{"id":"https:\/\/ror.org\/01znas443","id-type":"ROR","asserted-by":"publisher"}]},{"award":["451-03-33\/2026-03\/200007"],"award-info":[{"award-number":["451-03-33\/2026-03\/200007"]}],"id":[{"id":"https:\/\/ror.org\/01znas443","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>This study examined alterations in serum redox biomarkers before and one month after administration of the coronavirus disease 2019 (COVID-19) booster (third) doses across four vaccine regimens. A longitudinal cohort of 410 adults was analyzed following homologous Pfizer-BioNTech, Sinopharm [Vero Cell]-Inactivated, Sputnik V, or heterologous Sinopharm\/Pfizer vaccination. Serum total proteins, albumin, total thiols, nitrites, ferric-reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity were measured, with DPPH interpreted as an ex vivo surrogate of serum radical-scavenging capacity. Additional analyses included stratification by prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, multivariable regression, correlation analysis, effect-size estimation, and sensitivity testing. Booster vaccination was associated with modest but consistent decreases in DPPH activity, albumin, and total proteins, whereas FRAP, nitrite, and total thiol levels remained stable. This pattern supports a transient shift in antioxidant buffering capacity but, by itself, does not exclude oxidative stress, as direct oxidative damage markers were not assessed. The most pronounced changes were observed in Sinopharm-based regimens, particularly in the heterologous Sinopharm\/Pfizer group. Prior SARS-CoV-2 infection did not materially alter the qualitative response pattern, whereas older age and comorbidities were associated with greater declines in DPPH activity and albumin. Overall, the findings indicate a modest, transient redox-associated response following booster-induced immune activation and suggest that host-related factors, such as age and comorbidity burden, may accentuate short-term changes in antioxidant buffering capacity.<\/jats:p>","DOI":"10.3390\/ijms27104574","type":"journal-article","created":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T09:12:41Z","timestamp":1779268361000},"page":"4574","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Impact of COVID-19 Booster Vaccination on Serum Redox Homeostasis"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7540-0215","authenticated-orcid":false,"given":"Marija","family":"Vuk\u010devi\u0107","sequence":"first","affiliation":[{"name":"Institute for Biocides and Medical Ecology, Trebevi\u0107ka 16, 11030 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Du\u0161an Mihajlo","family":"Spasi\u0107","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vladimir","family":"Ke\u0161elj","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lena","family":"Platani\u0107 Arizanovi\u0107","sequence":"additional","affiliation":[{"name":"Independent Researcher, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5906-3298","authenticated-orcid":false,"given":"Tanja","family":"Grahovac","sequence":"additional","affiliation":[{"name":"Department of Physiology, Institute for Biological Research \u201cSini\u0161a Stankovi\u0107\u201d\u2014National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3700-688X","authenticated-orcid":false,"given":"Teodora","family":"Vidonja Uzelac","sequence":"additional","affiliation":[{"name":"Department of Physiology, Institute for Biological Research \u201cSini\u0161a Stankovi\u0107\u201d\u2014National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zorana","family":"Ore\u0161\u010danin Du\u0161i\u0107","sequence":"additional","affiliation":[{"name":"Department of Physiology, Institute for Biological Research \u201cSini\u0161a Stankovi\u0107\u201d\u2014National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1116-2035","authenticated-orcid":false,"given":"Aleksandra","family":"Nikoli\u0107-Koki\u0107","sequence":"additional","affiliation":[{"name":"Department of Physiology, Institute for Biological Research \u201cSini\u0161a Stankovi\u0107\u201d\u2014National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0932-889X","authenticated-orcid":false,"given":"Milan","family":"Nikoli\u0107","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1007\/s10930-020-09935-8","article-title":"Role of Oxidative Stress on SARS-CoV (SARS) and SARS-CoV-2 (COVID-19) Infection: A Review","volume":"39","author":"Suhail","year":"2020","journal-title":"Protein J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"593","DOI":"10.1038\/s41419-023-06102-6","article-title":"Immune Landscape and Redox Imbalance during Neurological Disorders in COVID-19","volume":"14","author":"Thakur","year":"2023","journal-title":"Cell Death Dis."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Smail, S.W., Ismail, B.A., Maghdid, I.S., Flaih, A.H., and Janson, C. 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