The experimental vaccines will be cross-vaccinated after available data of the investigational vaccine show that expected efficacy and good safety have been achieved (i.e., subjects in the study group will be vaccinated with placebo and those in the control group will be vaccinated with the investigational vaccine in the same schedule as stated above ). Eligible subjects will be stratified by age (<60 years of age and ≥60 years of age, the proportion of elderly people ≥60 years old is planned to be ≥25%) and randomly assigned into the study group and the control group at a ratio of 1:1 (14,000 in each group) to be intramuscularly administered with the investigational vaccine or placebo in a 2-dose regimen at an interval of 28 days. Why Should I Register and Submit Results?Īpproximately 28,000 subjects will be enrolled in this trial.
