Title Page
Contents
Abstract 9
Ⅰ. Introduction 11
1.1. COVID-19 vaccines and their efficacy 11
1.2. IGRA 12
1.3. Purpose of this study 13
Ⅱ. Materials and methods 14
2.1. Study population & study design 14
2.2. Sample preparation & assessment 17
2.2.1. T cell responses 17
2.2.2. Humoral responses 20
2.3. Statistical analysis 21
Ⅲ. Results 22
3.1. Immunogenicity of the unvaccinated group 22
3.2. Immunogenicity of the vaccinated groups 24
3.2.1. ChAdOx1-nCoV-19-vaccinated group 24
3.2.2. BNT162b2-vaccinated group 29
3.3. Comparison between vaccinated and unvaccinated groups 30
3.4. Comparison between two vaccinated groups 31
3.4.1. Comparison of IFN-γ responses 31
3.4.2. Comparison of anti-RBD IgG titers 32
3.5. Correlation between IFN-γ responses and anti-RBD IgG titers 33
Ⅳ. Discussion 36
4.1. The significance and implications of the study 36
4.2. Dynamics of cellular and humoral response following homologous and heterologous COVID-19 vaccination 37
4.3. The role of cellular response in individuals undergoing immune-modifying treatment 38
4.4. Low correlation between T cell and humoral response in SARS-CoV-2 vaccination 39
4.5. The role of cellular immunity against COVID-19 40
4.6. Limitations 41
Ⅴ. Conclusion 42
References 43
Abstract (in Korean) 48
Table 1. Demographic and basic characteristics of the study population 16
Table 2. IFN-γ responses and anti-RBD IgG titers after ChAdOx1-nCoV-19 and BNT162b2 vaccinations 23
Table 3. Correlation between IFN-γ responses and anti-RBD IgG titers by group 34
Figure 1. Flowchart of the total study participants throughout the study period. 15
Figure 2. Covi-FERON products for the measurement of IFN-γ responses. (A) Covi-FERON ELISA. (B) Covi-FERON tubes consisting of Nil (gray cap), Original spike... 19
Figure 3. IGRA and antibody assay results at the indicated time points after vaccination, with responder portions and percentages defined according to the... 28
Figure 4. A scatter diagram depicting the correlation between IFN-γ and anti-RBD IgG in all paired samples (N = 231). The blue line represents the trend line with a locally... 35