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- Title
Adaptive immune responses to two-dose COVID-19 vaccine series in healthy Canadian adults ≥ 50 years: a prospective, observational cohort study.
- Authors
Gaultier, Gabrielle N.; McMillan, Brynn; Poloni, Chad; Lo, Mandy; Cai, Bing; Zheng, Jean J.; Baer, Hannah M.; Shulha, Hennady P.; Simmons, Karen; Márquez, Ana Citlali; Bartlett, Sofia R.; Cook, Laura; Levings, Megan K.; Steiner, Theodore; Sekirov, Inna; Zlosnik, James E. A.; Morshed, Muhammad; Skowronski, Danuta M.; Krajden, Mel; Jassem, Agatha N.
- Abstract
To evaluate immune responses to COVID-19 vaccines in adults aged 50 years and older, spike protein (S)-specific antibody concentration, avidity, and function (via angiotensin-converting enzyme 2 (ACE2) inhibition surrogate neutralization and antibody dependent cellular phagocytosis (ADCP)), as well as S-specific T cells were quantified via activation induced marker (AIM) assay in response to two-dose series. Eighty-four adults were vaccinated with either: mRNA/mRNA (mRNA-1273 and/or BNT162b2); ChAdOx1-S/mRNA; or ChAdOx1-S/ChAdOx1-S. Anti-S IgG concentrations, ADCP scores and ACE2 inhibiting antibody concentrations were highest at one-month post-second dose and declined by four-months post-second dose for all groups. mRNA/mRNA and ChAdOx1-S/mRNA schedules had significantly higher antibody responses than ChAdOx1-S/ChAdOx1-S. CD8+ T-cell responses one-month post-second dose were associated with increased ACE2 surrogate neutralization. Antibody avidity (total relative avidity index) did not change between one-month and four-months post-second dose and did not significantly differ between groups by four-months post-second dose. In determining COVID-19 correlates of protection, a measure that considers both antibody concentration and avidity should be considered.
- Subjects
COVID-19 pandemic; COVID-19 vaccines; IMMUNE response; T cells; ANGIOTENSIN converting enzyme; ADULTS
- Publication
Scientific Reports, 2024, Vol 14, Issue 1, p1
- ISSN
2045-2322
- Publication type
Article
- DOI
10.1038/s41598-024-59535-0