Evaluation of the Safety and Immunogenicity of Simultaneously Administration of EV71 Vaccine and Influenza Vaccine

To further evaluate the feasibility of simultaneously administration of EV71 vaccine and flu vaccine, we design this clinical trial to test its immunogenicity and safety. 1134 subjects aged from 6 to 11 months old are divided into one experimental group and two control groups (control group A and B). 378 subjects from the experimental group will be simultaneously administrated with one dose of EV71 vaccine (0.5 ml) and one dose of influenza vaccine (0.25 ml). One month later, they are going to receive a second dose of EV71 vaccine and influenza vaccine, simultaneously. Blood samples are collected before the first vaccination, and one month following the second vaccination. 378 subjects from the control group A will be only administrated with two doses of EV71 vaccine (0.5 ml) (1 month apart). Blood samples are collected before the first vaccination, and one month following the second vaccination. 378 subjects from the control group B will be only administrated with two doses of influenza vaccine (0.25 ml) (1 month apart). Blood samples are collected before the first vaccination, and one month following the second vaccination. To evaluate the immunogenicity, we will detect and compare the neutralization antibody levels, the seroprotection rates, and antibody geometric mean concentrations. The safety of all groups will be monitored as well.