The purpose of this phase I study is to evaluate the safety of a Sabin Inactivated Poliovirus Vaccine (sIPV) in adults and children, and the safety and immunogenicity of it in infants. 20 adults aged 18~45 years and 20 children aged 4 years were only administered one dose of sIPV with medium D antigen content. 60 infants aged 2 months (60~90 days) were randomized to receive three doses of sIPV with medium D antigen content, 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 month 0, 1, 2 schedule. Serum samples were collected before the 1st dose and 30 days after the 3rd dose vaccination to assess the immunogenicity in infants. Adverse events occurring within 30 days after each dose were collected to assess the safety.

The purpose of this phase I study is to evaluate the safety of a Sabin Inactivated Poliovirus Vaccine (sIPV) in adults and children, and the safety and immunogenicity of it in infants. 20 adults aged 18~45 years and 20 children aged 4 years were only administered one dose of sIPV with medium D antigen content. 60 infants aged 2 months (60~90 days) were randomized to receive three doses of sIPV with medium D antigen content, 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 month 0, 1, 2 schedule. Serum samples were collected before the 1st dose and 30 days after the 3rd dose vaccination to assess the immunogenicity in infants. Adverse events occurring within 30 days after each dose were collected to assess the safety.

The antigen contents of type I, type II and type III polioviruses in the investigational and control vaccines were as follows: medium-dose Sabin IPV (15 DU, 45 DU and 45 DU), control Sabin IPV (30 DU, 32 DU and 45 DU), control Salk IPV (40 DU, 8 DU and 32 DU). All vaccines were in liquid form, 0.5 ml per dose.

Inclusion Criteria:

• Healthy volunteer aged 18~45 years with/without prior vaccination of poliovirus and without any contraindication for vaccination;
• Healthy volunteer aged 4 years with/without prior vaccination of poliovirus but without booster vaccination and any contraindication for vaccination;
• Healthy volunteer aged 2 months (60~90 days) 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:

• Women aged 18~45 years with positive urine pregnancy test, pregnant or lactating women, or women with pregnancy plans within 3 months;
• 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;