This study is a randomized, blinded and controlled phase II study to evaluate the safety and immunogenicity of a Sabin Inactivated Poliovirus Vaccine (sIPV) in Infants. A total of 600 infants aged 2 months (60~90 days) were randomized to receive five different vaccination regimens: three experimental groups (1, 2, and 3) received three doses of sIPV with high, medium, and low D antigen content, respectively, on the month 0,1,2 schedule; two control groups (4 and 5) received three doses of conventional IPV (cIPV, manufactured by Sanofi Pasteur) or sIPV (manufactured by the Institute of Medical Biology, the Chinese Academy of Medical Biology), respectively, on the same schedule. Serum samples were collected before the 1st dose and 30 days after the 3rd dose vaccination to assess the immunogenicity. Adverse events occurring within 30 days after each dose were collected to assess the safety.

Inclusion Criteria:

• Healthy volunteer aged 2 months (60~90 days) old without prior vaccination of poliovirus and any contraindication for vaccination;
• Guardians of the participants should be capable of understanding the written consent form, and such form should be signed prior to enrolment;
• Complying with the requirement of the study protocol;
• Axillary temperature ≤ 37.0 °C;

Exclusion Criteria:

• Preterm or low birth weight infants;
• Congenital malformation, developmental disorders, genetic defects, or severe malnutrition;
• History of polio;
• Severe nervous system disease (epilepsy, seizures or convulsions) or mental illness;
• History of allergy to any vaccine, or any ingredient of the vaccine, or serious adverse reaction(s) to vaccination, such as urticaria, dyspnea, angioneurotic edema, abdominal pain, etc;
• Autoimmune disease or immunodeficiency/immunosuppressive;
• Bleeding disorder diagnosed by a doctor (e.g., coagulation factor deficiency, coagulation disorder, or platelet disorder) , or significant bruising or coagulopathy;
• Serious chronic diseases, respiratory diseases, cardiovascular diseases, liver or kidney diseases or skin diseases;
• Mother of the participant has HIV infection;
• Acute illness or acute exacerbation of chronic disease within the past 7 days;
• Had a high fever within the past 3 days (axillary temperature ≥ 38.0°C);
• Receipt of any subunit or inactivated vaccine within the past 7 day;
• Receipt of any live attenuated vaccine within the past 14 days;
• Receipt of any blood product within the past 3 months;
• Any other factor that, in the judgment of the investigator, suggesting the volunteer is unsuitable for this study;