This is a randomized, double-blind, placebo control phase 1 clinical trial. Total 130 individuals were selected ,including adults (n=20), children(n= 20) and infants(n= 90). Adults were randomized to two groups A1(n=10) and A2(n=10).Group A1 received one dose of B ,one month later group A2 received one dose of A for safety observation. Children were randomized to two groups C1(n=10) and C2(n=10) and followed the same vaccination and safety observation procedures as adults. Infants were randomly allocated to three groups I-1,I-2,I-3 for safety and immunogenicity study. Group I-1 were vaccinated with three doses of C(n=15) or placebo (n=15) on day 0,30,60,serum samples were collected before and 30 days after dose 3 for detecting neutralization antibody. The same procedures were followed by GroupI-2 for B and group I-3 for A as groupI-1 with 30 days intermission.