Immunogenicity evaluation of primary polio vaccination schedule with inactivated poliovirus vaccines and bivalent oral poliovirus vaccine

Abstract Background To assess the immunogenicity of the current primary polio vaccination schedule in China and compare it with alternative schedules using Sabin or Salk-strain IPV (sIPV, wIPV). Methods A cross-sectional investigation was conducted at four sites in Chongqing, China, healthy infants aged 60–89 days were conveniently recruited and divided into four groups according to their received primary polio vaccination schedules (2sIPV + bOPV, 2wIPV + bOPV, 3sIPV, and 3wIPV). The sero-protection and neutralizing antibody titers against poliovirus serotypes (type 1, 2, and 3) were compared after the last dose. Results There were 408 infants completed the protocol. The observed seropositivity was more than 96% against poliovirus types 1, 2, and 3 in all groups. IPV-only groups induced higher antibody titers(GMT) against poliovirus type 2 (Median:192, QR: 96–384, P