A phase III clinical trial on the immunogenicity of a tetanus vaccine, adsorbed in individuals aged 18 years and above in China.

OBJECTIVE: To evaluate the immunogenicity of a tetanus vaccine, adsorbed (TTVA) in people aged 18 years and above. METHODS: A randomized, double-blinded, and positive controlled clinical trial was conducted in Bijie, Guizhou Province, China. Participants aged 18 years and above were recruited and randomly assigned 1:1 to receive the experimental (TTVA) or control tetanus vaccine, adsorbed (TT) vaccine. Serum samples were collected from all participants before vaccination, 30 days after vaccination, and 6 months after vaccination in the first 240 participants to detect tetanus toxoid IgG antibody levels. RESULTS: At 30 days after vaccination, the geometric mean concentration (GMC) of antibodies in the experimental group and the control group were 3.205 and 2.387 (P = 0.0012), the seroconversion rates were 89.07% and 87.47% (P = 0.6149), the seropositivity were 98.38% and 98.79% (P = 0.4850), and the geometric mean increase (GMI) were 35.529 and 27.604 (P = 0.0026), respectively. Six months after vaccination, the GMCs of antibodies in the experimental group and the control group were 1.025 and 0.803, respectively (P = 0.2119), the seropositivity were 98.25% and 95.73%, respectively (P = 0.4008), and the GMIs were 9.466 and 7.661, respectively (P = 0.2106). CONCLUSION: TTVA vaccine has good immunogenicity in people aged 18 years and above. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov, identifier NCT06120751.