Immunogenicity and safety of a meningococcal serogroups A and C tetanus toxoid conjugate vaccine in 3-month – 5-year old children: a phase III, single-center, randomized controlled trial

  Objective  To evaluate the immunogenicity and safety of a meningococcal serogroups A and C tetanus toxoid conjugate vaccine (MenAC-TT).

  Methods  From May 2016 to September 2017, in a phase III clinical trial, 1 799 participants aged 3-month to 5-year received test and control MenAC-TT vaccination at the ratio of 1 : 1; the participants aged 6 – 11 months and 3 – 5 months received a boost vaccination at month 18. Safety observation was conducted during 28 days after each vaccination. Blood samples were collected at the day 28 post vaccination and month 18 and the day 28 post boost in 6 – 11 months and 3 – 5 months participants.

  Results  The overall incidence of solicited adverse effects after vaccination in the 2 – 5 years, 12 – 23 months, 6 – 11 months and 3 – 5 months children of test groups were 33.11%, 58.28%, 75.33%, and 85.62%, respectively. The majority of the adverse effects were all gradeⅠ (mild) and no significant difference in the adverse effects was observed between the test and control group. After the primary vaccination, seroconversion rates were 98.60%, 100%, 100%, and 96.56% for MenA and 81.21%, 98.52%, 96.35%, 97.70% for MenC in the children of 4 test groups. The seroconversion rate was not significantly different between test and control groups of various ages, except for the children aged 6 – 11 months (χ² = 11.554 6, P = 0.000 7), indicating a non-inferiority of the MenAC-TT vaccination compared to the control. After boost, the seroconversion rates for MenA and MenC were approximately 100% in both 3 – 5 months and 6 – 11 months children of test groups.

  Conclusion  The meningococcal serogroups A and C tetanus toxoid conjugate vaccine is of good safety and high immunogenicity for 3-month to 5-year old susceptible children.