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

This study includes two stages. A clinical trial with an open‐label to evaluate the safety of Sabin Inactivated Poliovirus Vaccine (Vero cell) (2.5ml‐5 doses) (hereinafter referred to as "msIPV") in adults, children and infants in stageⅠ and a blinded, randomized and controlled clinical trial to evaluate the lot consistency immunogenicity, and safety of the msIPV in 2 months old infants in stage Ⅱ. A total of 1572 subjects including 24 adults aged 18‐49 years,24 children aged 4 years,1524 infants aged 2 months will be enrolled. StagesⅠ:72 healthy subjects, including 24 adults,24 children and 24 infants will be enrolled. 24 adults and 24 children will receive one dose of vaccine and 24 infants will receive 4 doses of vaccine according to the primary immunization schedule of 0,1,2 months and booster immunization schedule of 18 months. StagesⅡ:1500 infants aged 2 months will be randomly divided into 5 groups (Experimental Vaccine‐lot 1, Experimental Vaccine‐lot 2, Experimental Vaccine‐lot 3,IPV control group and single‐dose sIPV control group) according to the ratio of 1:1:1:1:1. Subjects in 3 experimental groups will receive 5‐dose sIPV produced by Sinovac for three lots, subjects in IPV control group will receive IPV produced by Pasteur, and subjects in single‐dose sIPV control group will receive single‐dose sIPV produced by Sinovac. All subjects will receive 4 doses of experimental or control vaccine according to the primary immunization schedule of 0,1,2 months, one dose of booster at 18 months of age.