Study of three kinds of primary immunization schedules with poliovirus vaccine

Abstract

Objective: To compare the immunogenicity of three kinds immunization programs with poliovirus vaccine. Methods: Healthy infants aged 2 months or over were selected and divided into three groups by complete randomization method. Basic immunization with Sabin inactivated poliovirus vaccine(sIPV) and bivalent oral poliovirus vaccine(bOPV) were completed. Three kinds of basic immunization procedures were 1sIPV+2bOPV,2sIPV+1bOPV and 3sIPV, respectively.Two qualified serums that before basic immunization and 28-42 days later were collected, and measured the poliovirus neutralizing antibody with microcell neutralization method. To compare the difference by analysis of variance, rank test and χ2 test. Results: After the basic immunization, 205 subjects of the positive conversion rate of poliovirus neutralizing antibodies of types Ⅰ, Ⅱ and Ⅲwere all higher than 97.00%, and the positive rates were all higher than 98.00%, the geometric mean titer (GMT) of neutralizing antibody was significantly higher than that before basic immunization in three groups.There were significant differences in the positive rate and GMT before and after basic immunization of typeⅠ, Ⅱand Ⅲ in the three (P<0.05). The highest GMT in three groups after basic immunization were all typeⅠ, followed by type Ⅲ, and the lowest in type Ⅱ. The GMT of type Ⅱin 2sIPV+1bOPV and 3sIPV groups were both higher than that in sIPV+2bOPV group. Conclution: After three kinds of basic immunization, the poliovirus neutralizing antibodies of serum were all at high levels in three groups, which could form an effective immune barrier against poliovirus. The immunogenicity of three kinds of basic immunization programs were all well, but there were certain differences of neutralizing antibodies among three kinds basic immunization programs. The immunogenicity in 2sIPV+1bOPV and 3sIPV groups against typeⅡpoliovirus were better than that in 1sIPV+2bOPV group.