A Multi-center, Open-labelled, Randomized, Controlled, Extended Phase Ⅲ Clinical Trial of sIPV Vaccine

Inclusion Criteria:

1. Infants of 6 weeks old (42-47 days); 2) For whom a parent/legal guardian has givenwritten informed consent after the study has been explained; 3) Be able to provide thevaccination records after birth; 4) Negative results in SARS-CoV-2 rapid antigen testing,within 24 hours before enrollment; 5) The participant's mother was tested negative for HIV,Syphilis, Hepatitis A, Hepatitis B infection during or before (during pregnancy) herchild's enrollment to this study (the test result should be provided, and that obtainedduring pregnancy is acceptable).

Exclusion Criteria:

1. History of polio vaccination (except the OPV at birth); 2) Prior vaccination withroutine infant vaccines against Diphtheria, Tetanus, Pertussis, Haemophilus influenzae typeb (Hib), Pneumococcal or rotavirus; 3) History of severe allergic reaction after previousvaccinations or hypersensitivity to any vaccine component; 4) Infants with premature labor (delivery before week 37 of gestation) and low body weight (birth body weight is <2500 g);
2. Infants with difficult labor at birth, asphyxiation rescue and history of nervous systeminjury; 6) Congenital malformation or development disorder, genetic defect, severemalnutrition, etc.; 7) Autoimmune disease or immunodeficiency/immunosuppression; 8)Patients with serious chronic diseases (such as Down's syndrome, diabetes, sickle cellanemia, or neurological disorders); 9) Abnormal coagulation functions (such as coagulationfactor deficiency, blood coagulation disease and blood platelet disorders) or obviousbruise or blood coagulation disorders diagnosed by the doctors; 10) Those who have receivedimmunosuppressant therapy, cytotoxic drug therapy and inhaled corticosteroid therapy (excluding the corticosteroid aerosol therapy for allergic rhinitis and surfacecorticosteroid therapy for acute non-complicated dermatitis); 11) The volunteer hasreceived blood products before inoculation of the trial vaccine; 12) The volunteer hasreceived other study drugs within 30 days before inoculation of the trial vaccine; 13) Thevolunteer has received live attenuated vaccines within 14 days before inoculation of thetrial vaccine; 14) The volunteer has received subunit or inactivated vaccines within 7 daysbefore inoculation of the trial vaccine; 15) Various acute diseases or acute exacerbationof chronic diseases within recent 7 days; 16) Significant acute disease or chronicinfection within the previous 7 days or axillary temperature equal and more than 37.3℃prior to vaccination in the present study; 17) The volunteer has any other factors whichare unsuitable for participation in the clinical trial as judged by the investigators.