Comparative analysis of SARS-CoV-2 immune memory in vaccinated and hybrid individuals two years post-exposure
- 1Florida Atlantic University, Charles E. Schmidt College of Medicine, Department of Medicine, 777 Glades Road, PO Box 3091, Boca Raton, FL, 33431, USA
- 2Corresponding author.
Abstract
Assessing vaccine effectiveness and longevity through measurements of vaccine-induced serum antibodies, as well as memory B and T cells in circulating blood years after vaccination, serves as an indicator of protection and durability. Here, we build upon studies by assessing serum levels of SARS-CoV-2 spike (S) protein–specific immunoglobulins, as well as the status of S protein–specific immune memory in both vaccinated individuals and those with hybrid immunity. We aimed to determine whether the patterns of immune memory reported up to six months post-vaccination in the literature still remains two years after vaccine exposure. Both vaccination and hybrid immunity elicited durable and robust antigen-specific T- and B-cell responses, with memory subsets remaining detectable for up to two years post-exposure. Individuals with hybrid immunity showed greater expansion of central, effector memory, and effector T-cell subsets and produced more IFN-γ per cell upon antigenic stimulation, indicating superior functional quality of effector cells. Our B-cell analyses revealed that hybrid-immune individuals had a higher frequency of S-specific B cells that, upon expansion, differentiated more rapidly into plasmablasts and plasma cells, resulting in increased numbers of these subsets. In contrast, vaccinated individuals exhibited higher S1-specific IgG levels in both culture supernatants and serum. Given the limited number of independent donors, these findings provide an exploratory characterization of long-term vaccine- and hybrid-immunity responses in these populations. Taken together, our findings indicate that approximately two years after exposure, hybrid-immune individuals maintain robust cellular immune responses, while vaccinated individuals retain higher S1-specific IgG antibody responses.
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BibTeX
@article{lee2026comparative,
title = {{Comparative analysis of SARS-CoV-2 immune memory in vaccinated and hybrid individuals two years post-exposure}},
author = {Czdari Lee and Imtisal Imran and Sara Thomas and Mahyar Nouri-Shirazi},
journal = {Clinical Immunology Communications},
year = {2026},
month = oct,
doi = {10.1016/j.clicom.2026.100144},
url = {https://doi.org/10.1016/j.clicom.2026.100144},
note = {CC BY},
}
RIS
TY - JOUR
TI - Comparative analysis of SARS-CoV-2 immune memory in vaccinated and hybrid individuals two years post-exposure
AU - Czdari Lee
AU - Imtisal Imran
AU - Sara Thomas
AU - Mahyar Nouri-Shirazi
PY - 2026
DA - 2026/10/30
JO - Clinical Immunology Communications
DO - 10.1016/j.clicom.2026.100144
UR - https://doi.org/10.1016/j.clicom.2026.100144
AB - Assessing vaccine effectiveness and longevity through measurements of vaccine-induced serum antibodies, as well as memory B and T cells in circulating blood years after vaccination, serves as an indicator of protection and durability. Here, we build upon studies by assessing serum levels of SARS-CoV-2 spike (S) protein–specific immunoglobulins, as well as the status of S protein–specific immune memory in both vaccinated individuals and those with hybrid immunity. We aimed to determine whether the patterns of immune memory reported up to six months post-vaccination in the literature still remains two years after vaccine exposure. Both vaccination and hybrid immunity elicited durable and robust antigen-specific T- and B-cell responses, with memory subsets remaining detectable for up to two years post-exposure. Individuals with hybrid immunity showed greater expansion of central, effector memory, and effector T-cell subsets and produced more IFN-γ per cell upon antigenic stimulation, indicating superior functional quality of effector cells. Our B-cell analyses revealed that hybrid-immune individuals had a higher frequency of S-specific B cells that, upon expansion, differentiated more rapidly into plasmablasts and plasma cells, resulting in increased numbers of these subsets. In contrast, vaccinated individuals exhibited higher S1-specific IgG levels in both culture supernatants and serum. Given the limited number of independent donors, these findings provide an exploratory characterization of long-term vaccine- and hybrid-immunity responses in these populations. Taken together, our findings indicate that approximately two years after exposure, hybrid-immune individuals maintain robust cellular immune responses, while vaccinated individuals retain higher S1-specific IgG antibody responses.
SN - 2772-6134
ER -