2022年 · 第102卷第04期

To evaluate the immunogenicity and safety of SARS-CoV-2 inactivated vaccine (KCONVAC) in healthy adults, the Jiangsu Provincial Center for Disease Control and Prevention conducted randomized double-blind controlled phase I and II clinical trials in healthy subjects. A total of 60 subjects were enrolled in the phase I clinical trial and randomly assigned to the vaccine group (5 μ g or 10 μ g) and the placebo control group at a ratio of 4:1, both of which were immunized for 0-14 days. The phase II clinical trial was 0-14 d and 0-28 d immunization program groups, and a total of 500 subjects were enrolled. Subjects in each group were vaccinated with 5 μ g and 10 μ g of experimental vaccine or placebo at a ratio of 2:2:1. The primary safety endpoint of the Phase I trial was the incidence of adverse reactions/events within 28 days after vaccination. The primary immunogenicity endpoints of the phase II trial were SARS-CoV-2 neutralizing antibody titer, positive conversion rate and anti-receptor binding domain immunoglobulin G positive conversion rate 28 days after the second dose of vaccine.

Currently, large-scale vaccination of CoronaVac, an inactivated vaccine against SARS-CoV-2, is underway in many countries. This study aims to evaluate the immunogenicity, safety results after the 3rd dose of CoronaVac booster shot, and the immune durability results of the 2-dose immunization program in healthy adults over 18 years of age. The first single-center, double-blind, randomized, placebo-controlled phase II clinical trial was conducted in Jiangsu Province. It was divided into 0-14 d and 0-28 d immunization programs. Each immunization program was divided into 3 μ g vaccine group, 6 μ g vaccine group and control group, and the ratio of subjects was 2:2:1. Half of the subjects in each immunization program received the 3rd dose (window 30 d) 28 d after the 2nd dose (groups 1a-14d-2m and 2a-28d-2m), and the other half received the 3rd dose (window 60 d) 6 months after the 2nd dose (groups 1b-14d-8m and 2b-28d-8m). Another phase II clinical trial was carried out in Hebei Province. Subjects aged 60 years and older were vaccinated with 1.5 μ g, 3 μ g or 6 μ g vaccine or placebo, respectively. The first two doses were separated by 28 days, and the second and third doses were separated by 6 months (window period 90 days) (group 3-28d-8m). This study mainly evaluated the geometric mean titer (GMT), geometric mean titer growth factor (GMI) and positive conversion rate of SARS-CoV-2 neutralizing antibodies, and focused on the approved 3 μ g vaccine.

Although SARS-CoV-2 infection causes milder symptoms in children and adolescents, there is still a need for effective means to control the spread of SARS-CoV-2 in this group of people to achieve the purpose of controlling infectious diseases. From August to September 2020, Henan Provincial Center for Disease Control and Prevention conducted randomized, double-blind controlled phase I and II clinical trials of novel coronavirus inactivated vaccine in people aged 3-17 years. Three age groups were divided into 3-5, 6-12 and 13-17 years old. Subjects in each age group were randomly divided into 4 groups in the ratio of 1:1:1:1, and were vaccinated with 2 μ g, 4 μ g, 8 μ g vaccine or placebo according to the immunization program of 0-28-56 d. The safety of the vaccine was evaluated by collecting adverse events from the first dose to 30 days after completion of the full course of immunization. The immunogenicity of the vaccine was evaluated by measuring the serum neutralizing antibody levels of the subject after vaccination.