This is a multi-country, multi-center, open-labelled, randomized, controlled, extended phase Ⅲ clinical trial. Totally 1440 healthy infants of 6 weeks old (42-47 days) are planned to be enrolled, and then randomized in a 1:1:1:1 ratio into four groups, i.e., co-administration group 1 (group C1), co-administration group 2 (group C2), staggered administration group 1 (group S1) and staggered administration group 2 (group S2). Participants in group C1 and C2 will receive sIPV at 6,10, 14 weeks of age, administered concomitantly with routine infant vaccine (may include DTP-HepB-Hib vaccine, PCV10 or rotavirus vaccine in accordance with the local routine vaccination schedule). Participants in group S1 will receive sIPV at 6,10,14 weeks of age, and receive routine infant vaccines at 8,12,16 weeks of age. Participants in group S2 will receive routine infant vaccines at 6,10,14 weeks of age, and receive sIPV at 8,12, 16 weeks old.~For all the Participants, the immediate reactions within 30 minutes after each dose of vaccination will be observed on site. Guardians of participants will utilize the diary card to record solicited adverse events from the time of vaccination for 7 days post-vaccination of each dose. From the time of the first vaccination and 28 days post-vaccination of the last dose, unsolicited adverse events and any SAEs will be required to recorded in the diary card.~About 3 ml venous blood will be collected before the first vaccination and 28 days (+7) days after the last vaccination of sIPV or routine vaccines. Antibodies level will be determined using the collected sera for immunogenicity evaluation. Group C1 and S1 will be compared in terms of immunogenicity against polio; Group C2 and S2 will be compared in terms of immunogenicity against diphtheria, Tetanus, Pertussis, Hepatitis B, Hib and Pneumococcal.
This study is designed to study the immunogenicity and safety of sIPV co-administered with other routine infant vaccines. According to the national immunization schedule of Bangladesh and Pakistan, sIPV was administered concomitantly with PCV10, DTP-HeB-Hib and other vaccines at 6, 10 and 14 weeks old. Thus, this study set up the concomitant vaccination schedule according to the real practice in study area. The primary hypothesis of this study is the seroconversion rate of polio vaccination when administered concomitantly with routine vaccines, is non-inferior to that when administered alone; the secondary hypothesis of this study is the seropositivity rate of diphtheria, tetanus, and pertussis when routine vaccines are administered concomitantly with sIPV, is non-inferior to that administered without sIPV.