To Evaluate the Immunogenicity and Safety of Sequential Immunization Schedules of Sabin IPV and bOPV

A phase 4 clinical trial is designed to evaluate the safety and immunogenicity of different sequential immunization schedules of Sabin IPV and bOPV. To be specific, the subjects were divided into 3 groups. Group 1 received Sabin‐IPV+bOPV+bOPV respectively at the age of 2,3,4 months old. Group 2 received Sabin‐IPV+Sabin‐IPV+bOPV respectively at the age of 2,3,4 months old. Group 3 received Sabin‐IPV+Sabin‐IPV+Sabin‐IPV respectively at the age of 2,3,4 months old. Blood samples were collected before vaccination and 30 days after the third dose. Neutralization antibody against type I, Type II and Type III poliomyelitis virus were detected to evaluate the seroprotection rates and antibody geometric mean concentrations. The safety of the 3 immunization schedule groups were also monitored.