Tính sinh miễn dịch của vắc xin nanocovax phòng COVID-19 trên người Việt Nam tình nguyện

Abstract

Objective: To evaluate the Immunogenicity of the Nanocovax vaccine with dose 25µg against COVID-19 produced by Nanogen in Vietnamese volunteers aged 18 years and older. Subject and method: Randomized controlled (placebo) blinded phase 2 and 3a vaccine clinical trials studies were conducted on healthy volunteers, aged 18 years and older according to a 2-dose regimen, 28 days apart. Immunogenicity was assessed based on the quantitative results of IgG antibody concentration against protein S (AntiS-IgG); Test results assessing SARS-CoV-2 virus neutralization activity (Surrogate Virus Neutrolization Test: sVNT) and test results quantifying of live SARS-CoV-2 neutralizing antibody titers with 50% plaque reduction neutralization test (PRNT₅₀) based on cell culture. Result: At day 42 after the first injection, the IgG concentration increased with the geometric mean content (GMCs) of AntiS-IgG being 57.90U/ml, equivalent to 1,262.22BAU/ml; and the geometric mean fold rise (GMFR) of AntiS-IgG reached 227.4 times compared to before injection. The seroconversion rate of the Nanocovax group reached 99.4%. The proportion of subjects vaccinated with nanocovax 25µg vaccine with virus neutralization activity by alternative neutralization test (sVNT) was high (99.03%). PRNT50 results in the vaccinated group: 91.9% of serum samples neutralized live virus on the Wuhan strain, the Delta strain (India) was 62.2%, and the Alpha strain (UK) was 80.0%. Conclusion: Nanocovax 25µg vaccine meets the requirements for immunogenicity in volunteers.