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Sci Rep
. 2026 Jun 3.
doi: 10.1038/s41598-025-23065-0. Online ahead of print.
Effects of the third dose of the coronavirus disease vaccine in healthy adults and immunosuppressed patients
Shinyoung Kim # 1 , Mi-Seon Bang 1 , Munawir Muhammad 1 2 , Da-Yeon Lee 1 , Da Young Kim 1 , Jun-Won Seo 1 , Na Ra Yun 1 , Choon-Mee Kim 3 , Jae-Hoon Ko 4 , Jinyoung Yang 4 , Kyong Ran Peck 4 , Kyo Won Lee # 5 , Sung-Hoon Jung 6 , Hyun-Jin Bang # 6 , Woo Kyun Bae 6 , Tae-Jong Kim 7 , Kyeong Hwan Byeon 8 , Sung-Han Kim 9 , Ju-Hyung Lee 10 , Dong-Min Kim # 11 12
Affiliations
This study evaluated the antibody and cellular immune responses before and after the third dose of the coronavirus disease 2019 (COVID-19) vaccine in healthy adults and immunocompromised hosts (IC). At baseline (before the third vaccination), healthy adults exhibited a 100% seropositivity rate with significantly higher antibody titers compared to IC, who showed a lower seropositivity rate (> 90%) and markedly reduced antibody levels. Among the immunocompromised subgroups, kidney transplantation (KT) recipients had the lowest seropositivity rate (73.3%) and significantly lower antibody titers than patients with rheumatoid arthritis (RA), whose responses were comparable to those of the healthy adults. Following the third vaccine dose, all groups demonstrated increased seropositivity rate; however, KT recipientss continued to show significantly lower antibody titers and interferon (IFN)-γ levels. At six months after the thirdvaccination, approximately 93.2% of the KT recipients remained seropositive; however, their median antibody titers and neutralizing activity remained significantly lower than those observed in other groups. T-cell responses were also substantially reduced in ICs, particularly among KT recipients, who consistently exhibited the lowest IFN-γ levels throughout the observation period. Across all groups and time points, neutralizing antibodies (NAb) against the Omicron variant were lower than those against the wild-type virus, with KT recipients demonstrating almost no neutralizing activity against Omicron, even after receiving the booster dose. Although the third dose improved immune responses in most of the immunocompromised subgroups, KT recipients consistently exhibited weak antibody and T-cell responses, especially against Omicron. The correlation between antibody titers and the IFN-γ release assay was weak and nonsignificant in healthy adults, whereas it was strong and significant in IC. Furthermore, baseline immune parameters were more predictive of post-vaccination responses in ICs than healthy adults.
Keywords: COVID-19; SARS-CoV-2; Vaccination.
. 2026 Jun 3.
doi: 10.1038/s41598-025-23065-0. Online ahead of print.
Effects of the third dose of the coronavirus disease vaccine in healthy adults and immunosuppressed patients
Shinyoung Kim # 1 , Mi-Seon Bang 1 , Munawir Muhammad 1 2 , Da-Yeon Lee 1 , Da Young Kim 1 , Jun-Won Seo 1 , Na Ra Yun 1 , Choon-Mee Kim 3 , Jae-Hoon Ko 4 , Jinyoung Yang 4 , Kyong Ran Peck 4 , Kyo Won Lee # 5 , Sung-Hoon Jung 6 , Hyun-Jin Bang # 6 , Woo Kyun Bae 6 , Tae-Jong Kim 7 , Kyeong Hwan Byeon 8 , Sung-Han Kim 9 , Ju-Hyung Lee 10 , Dong-Min Kim # 11 12
Affiliations
- PMID: 42236751
- DOI: 10.1038/s41598-025-23065-0
This study evaluated the antibody and cellular immune responses before and after the third dose of the coronavirus disease 2019 (COVID-19) vaccine in healthy adults and immunocompromised hosts (IC). At baseline (before the third vaccination), healthy adults exhibited a 100% seropositivity rate with significantly higher antibody titers compared to IC, who showed a lower seropositivity rate (> 90%) and markedly reduced antibody levels. Among the immunocompromised subgroups, kidney transplantation (KT) recipients had the lowest seropositivity rate (73.3%) and significantly lower antibody titers than patients with rheumatoid arthritis (RA), whose responses were comparable to those of the healthy adults. Following the third vaccine dose, all groups demonstrated increased seropositivity rate; however, KT recipientss continued to show significantly lower antibody titers and interferon (IFN)-γ levels. At six months after the thirdvaccination, approximately 93.2% of the KT recipients remained seropositive; however, their median antibody titers and neutralizing activity remained significantly lower than those observed in other groups. T-cell responses were also substantially reduced in ICs, particularly among KT recipients, who consistently exhibited the lowest IFN-γ levels throughout the observation period. Across all groups and time points, neutralizing antibodies (NAb) against the Omicron variant were lower than those against the wild-type virus, with KT recipients demonstrating almost no neutralizing activity against Omicron, even after receiving the booster dose. Although the third dose improved immune responses in most of the immunocompromised subgroups, KT recipients consistently exhibited weak antibody and T-cell responses, especially against Omicron. The correlation between antibody titers and the IFN-γ release assay was weak and nonsignificant in healthy adults, whereas it was strong and significant in IC. Furthermore, baseline immune parameters were more predictive of post-vaccination responses in ICs than healthy adults.
Keywords: COVID-19; SARS-CoV-2; Vaccination.