The study describe 1 year durability of humoral and cellular immune responses in 150 individuals who received COVID-19 inactivated vaccine. all participants were recruited aged between 18 and 59 years old. Every participant was familiarized with the aim of the study and asked to sign an informed consent agreement, and be required blood sampling at the day 0 of first dose vaccine and 1 month, 3 months, 6 months and 12 months after fully vaccination separately. From every sample, 10 ml, 10 ml, and 5 ml were dispensed in three vacuum blood collection tubes. Peripheral blood lymphocytes cell (PBMC) were isolated with the two 10 ml samples contained heparin to detect immune memory cells and cytokines. RBD-IgG and neutralizing antibody be detected by 5ml sample from separating gel vacuum tubes. every individual conducted a detailed analysis comparing neutralizing antibody, TEM, TCM , and report on the cellular and humoral immunity 1 year after accept COVID-19 vaccine.
Study Type
OBSERVATIONAL
Enrollment
150
Beijing Center for Disease Control and Prevention
Beijing, China
Durability of humoral and cellular immune responses
The humoral immunogenicity outcomes include the RBD-specific IgG titers and neutralising antibodies amounts at 1, 3, 6, and 12 months after the second shot. The positive cutoff for RBD-specific IgG antibodies was defined as the sample cutoff (S/CO) value ≥1.0. Seroconversion of neutralising antibodies was defined as a change from seronegative at baseline to seropositive or a four-fold titre increase. The positive cutoff of the titre for neutralising antibodies was 1/4. The cellular immune response outcomes measured by ICS assays across the blood collection time points.the percentage of RBD-specific CD4+ CD8+ memory T cells after vaccination.
Time frame: 12 months after fully vaccination
The dynamic variation of the level of antibody
RBD-IgG and neutralizing antibody level after vaccination at 1,3 and 6 ,12months vaccination.
Time frame: 1，3，6 , 12 month
Cytokine secretion by peripheral blood mononuclear cells
To study the cytokine production of PBMC after stimulation with RBD after vaccination at 1,3,6 and 12 months vaccination,for examples IL-2,IL-5,IFN and GrB.
Time frame: 1,3,6,12 month
TCM and TEM amount varies at different time points
The dynamic variation of specificity TCM and TEM after vaccination at 1,3,6 and 12 months vaccination.
Time frame: 1,3,6,12 month
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