Randomized, blind, controlled phase III clinical trial: Assessing the immunogenicity and safety of freeze-dried human rabies vaccine (vero cell) with a 4-dose regimen (2-1-1) in a 10–60 year-old demographic

Abstract

ObjectiveThe aim of this study is to demonstrate that the freeze-dried human rabies vaccine (Vero cell), administered in a four-dose schedule (2-1-1) to the 10–60 years old population, has immunogenicity that is not inferior to the approved five-dose schedule and similar vaccines with a four-dose schedule, and to evaluate its safety. MethodA total of 1800 individuals were enrolled and divided into three groups: four-dose test group, four-dose control group, and five-dose control group. The rabies virus neutralizing antibodies were measured using the Rapid Fluorescent Focus Inhibition Test to assess immunogenicity, and the incidence of adverse events and serious adverse events were statistically analyzed. ResultsThe seroconversion rates 14 days after the first dose and 14 days after the complete course of vaccination were 100% in all three groups. The antibody GMC of the four-dose test group was higher than that of the five-dose control group, but slightly lower than the four-dose control group. Seven days after the first dose, both four-dose regimen groups showed higher seroconversion rates and antibody GMCs compared to the five-dose regimen group, proving that the immunogenic effect of the four-dose regimen seven days post-first vaccination is superior to the five-dose regimen. The overall incidence of adverse events showed no significant difference between the four-dose test group and the five-dose control group, but was significantly lower in the four-dose test group compared to the four-dose control group. ConclusionThe vaccine in the four-dose test group is equivalent in immunogenic effect to the four-dose control group vaccine and superior to the five-dose control group vaccine; the safety of the vaccine in the four-dose test group is equivalent to the five-dose control group vaccine and superior to the four-dose control group vaccine. clinicaltrials.gov number: NCT05549908.