Clinic Trial to Evaluate the Safety and Immunogenicity by Different Sequential Schedules of bOPV and IPV

According to the requirement of the Strategy of Polio Eradication & Endgame Strategic Plan 2013‐2018, bivalent oral attenuated live poliomyelitis vaccine against type 1 and 3 (bOPV) and inactivated poliomyelitis vaccine made by Sabin strain (sIPV) need to be used to eradiation both the wild poliovirus and vaccine‐derived poliovirus. By studying different sequential immunization schedules of bOPV(candy/liquid) with IPV(cIPV/sIPV) to evaluate the safety and immunogenicity of bivalent oral poliomyelitis vaccine co‐administered with IPV in healthy Infants. A randomized, double blind, single center and parallel phase Ⅲ clinic trial was performed in Guangxi Province in China. A total of 1200 infants at 2 months old were selected, and randomly divided into 12 different groups (100 individuals were included in each group) administrated the vaccines at 0, 28, 56 days schedule. The bOPV(bivalent oral attenuated live poliomyelitis vaccine against type 1 and type 3), tOPV(trivalent OPV against type 1, type 2 and type 3), sIPV (Inactivated Poliomyelitis Vaccine Made from Sabin Strains)and conventional IPV (Inactivated Poliomyelitis Vaccine Made from Wild Polio Strains) were assign to different group of sequential immunization schedules. The detail of each group as following: 1)1‐dose cIPV + 2‐doses bOPV (Candy); 2)1‐dose sIPV + 2‐doses bOPV (Candy); 3)2‐doses cIPV + 1‐dose bOPV (Candy); 4)2‐doses sIPV + 1‐dose bOPV (Candy); 5)2‐doses cIPV + 1‐dose tOPV (Candy); 6)2‐doses sIPV + 1‐dose tOPV (Candy); 7)1‐dose cIPV + 2‐doses bOPV (Liquid); 8)1‐dose sIPV + 2‐doses bOPV (Liquid); 9)2‐doses cIPV + 1‐dose bOPV (Liquid); 10)2‐doses sIPV + 1‐dose bOPV (Liquid); 11)2‐doses cIPV + 1‐dose tOPV (Liquid); 12)2‐doses sIPV + 1‐dose tOPV (Liquid). Blood Sample was collected before vaccination and 28 days after the third dose of vaccination. Neutralization antibody against type I, Type I and Type III poliomyelitis virus were detected to evaluate the seroprotection rates and antibody geometric mean concentrations. The safety of different sequential schedule immunization for the vaccines also been monitored. The first 10% of subjects in each research site，fecal samples were collected to test polio virus shedding.The 7 times are before the second dose immunization and the 7、14、28 days after the second and the third dose immunization.