The purpose of this study is to evaluate the immunogenicity and safety of different sequential immunization strategies by Sabin IPV and bOPV in Chinese infants.

Inclusion Criteria:

• Parent/legal acceptable representative is willing and able to understand the protocol requirements and provide informed consent.
• Participant is aged ≥ 60 days to ≤ 75 days.
• Participant without preventive inoculation of polio vaccine and previous history of Polio.
• Subject and parent/guardian able to attend all scheduled visits and comply with all trial procedures.
• Body temperature ≤ 37.5℃.

Exclusion Criteria:

• Known allergy to any constituent of the vaccine.
• Known acute illness, severe chronic disease, acute exacerbation of chronic disease and fever.
• Known or suspected impairment of immunologic function, or receipt of immunosuppressive therapy or immunoglobulin since birth.
• Reported the history of allergies, convulsions, epilepsy, mental illness and brain disease and clear serious systemic reaction.
• Known bleeding disorder.
• Receipt of the whole blood, blood plasma or immunoglobulin before the trial vaccination.
• Reported the history of acute illness had need systemic antibiotics or antiviral treatment of infections in the 7 days preceding the trial vaccination.
• An acute illness with or without fever (temperature ≥ 38.0℃) in the 3 days preceding enrollment in the trial.
• Participation in any other intervention clinical trial.
• Any condition which, in the opinion of the investigator, would pose a health risk to the subject or interfere with the vaccine.