Study on Antibody Persistence and Immune Memory of Inactivated COVID-19 Vaccine

Study Overview
=================
Brief Summary
-----------------
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.

Official Title
-----------------
A Prospective Cohort Study on Antibody Persistence and Immune Memory After Two Doses of Inactivated COVID-19 Vaccine in 150 People

Conditions
-----------------
COVID-19

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Working at the CDC Between the ages of 18 and 59 Healthy Not vaccinated with COVID-19 vaccine Agreed to take a blood sample Exclusion Criteria: who cannot take the COVID-19 vaccine due to some personal reasons history of SARS-CoV, SARS-CoV-2, or Middle East respiratory syndrome infection high-risk epidemiology history within 14 days before enrolment (eg, travel or residence history in communities with case reports, or contact history with someone infected with SARS-CoV-2) axillary temperature of more than 37·0℃ history of allergy to any vaccine component.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 59 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 12 months after fully vaccination | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The dynamic variation of the level of antibody | RBD-IgG and neutralizing antibody level after vaccination at 1,3 and 6 ,12months vaccination. | 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. | 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. | 1,3,6,12 month | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Inactivated vaccine, cohort study, Antibody persistence, cellular immunity