Safety of Sabin Inactivated Poliovirus Vaccine in Adults, Children and Infants and Lot Consistency Immunogenicity, and Safety of the msIPV in 2 Months Old Infants

Inclusion Criteria: Inclusion criteria for adult subjects : * Healthy adults aged 18-49 days; * Proven legal identification; * The subject can understand and voluntarily sign the informed consent form. Inclusion criteria for children subjects : * Healthy children aged 4 years old; * Subjects who have completed primary immunization with 3 doses of sIPV vaccine; * Proven legal identification and vaccination certificate; * The subject and/or guardian can understand and voluntarily sign the informed consent form. Inclusion criteria for infant subjects: * Healthy infants aged 2 months (60\~89 days) * Proven legal identification and vaccination certificate; * The subject and/or guardian can understand and voluntarily sign the informed consent form. Exclusion Criteria: Exclusion criteria for adult subjects: * Women aged 18 to 49 years, positive urine pregnancy test, pregnant women, breastfeeding women, or planning to become pregnant within 3 months; * Previous history of vaccination of sIPV vaccine; * Allergy history, history of asthma, including allergy history to vaccine or vaccine components, serious adverse reactions to the vaccine, such as urticaria, dyspnea, angioneurotic edema or stomachache, etc; * Congenital malformation or developmental disorder, genetic defect, serious malnutrition, etc.; * Autoimmune disease or immunodeficiency/immunosuppression; * Thyroid disease or thyroidectomy history, absence of spleen, functional absence of spleen, and any conditions resul…