Immunogenicity of meningococcal polysaccharide conjugate vaccine as a replacement for meningococcal polysaccharide vaccine in children in Guangzhou, China.

To assess the durability of antibody persistence after substitution of the MPCV vaccine for the MPSV-A vaccine in children, an observational study was conducted in children who voluntarily received two doses of MPCV-AC instead of MPSV-A between March 2017 and March 2018 in Guangzhou, China. In total, 131 and 47 participants were enrolled in the 3-year-old and 6-year-old groups, respectively. In the 3-year-old group, the seroprotection rate and GMT values for Men A and Men C were raised significantly after 1-month post- dose 1 MPSV booster vaccination. All immune indicators were significantly lower in pre- dose 1 MPSV booster vaccination in the 3-year-old group than after pre- dose 2 MPSV booster vaccination in the 6-year-old group. While no significant differences were found in most immune indicators between the 1-month post- dose 1 MPSV booster vaccination in the 3-year-old group and pre- dose 2 MPSV booster vaccination in 6-year-old group. The substitute meningococcal immunization schedule showed a good immunogenicity in young children, and good sequential immunogenicity with MPSV booster immunization.