Abstract
BackgroundLong-term protection against meningococcal disease is associated with persistence of post-vaccination antibodies at protective levels. We evaluated the bactericidal antibody persistence and safety of the quadrivalent meningococcal serogroups A, C, W and Y tetanus-toxoid conjugate vaccine (MenACWY-TT) and the meningococcal polysaccharide serogroups A, C, W, and Y vaccine (MenACWY-PS) up to 5 years post-vaccination.MethodsThis phase IIb, open, randomized, controlled study conducted in the Philippines and Saudi Arabia consisted of a vaccination phase and a long-term persistence phase. Healthy adolescents and adults aged 11–55 years were randomized (3:1) to receive a single dose of MenACWY-TT (ACWY-TT group) or MenACWY-PS (Men-PS group). Primary and persistence results up to 3 years post-vaccination have been previously reported. Antibody responses against meningococcal serogroups A, C, W, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA, cut-off titers 1:8 and 1:128) at Year 4 and Year 5 post-vaccination. Vaccine-related serious adverse events (SAEs) and cases of meningococcal disease were assessed up to Year 5.ResultsOf the 500 vaccinated participants, 404 returned for the Year 5 study visit (Total Cohort Year 5). For the Total Cohort Year 5, 71.6–90.0 and 64.9–86.3 % of MenACWY-TT recipients had rSBA titers ≥1:8 and ≥1:128, respectively, compared to 24.8–74.3 and 21.0–68.6 % of MenACWY-PS recipients. The rSBA geometric mean titers (GMTs) remained above the pre-vaccination levels in both treatment groups. Exploratory analyses suggested that both rSBA GMTs as well as the percentages of participants with rSBA titers above the cut-offs were higher in the ACWY-TT than in the Men-PS group for serogroups A, W and Y, with no apparent difference for MenC. No SAEs related to vaccination or cases of meningococcal disease were reported up to Year 5.ConclusionThese results suggest that a single dose of MenACWY-TT could protect at least 72 % of vaccinated adolescents and adults against meningococcal disease at least 5 years post-vaccination.Trial registrationClinicalTrials.gov NCT00356369Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-1138-y) contains supplementary material, which is available to authorized users.
Highlights
Long-term protection against meningococcal disease is associated with persistence of post-vaccination antibodies at protective levels
Results of a randomized study enrolling 500 participants showed Quadrivalent meningococcal vaccine (MenACWY)-tetanus toxoid (TT) to be non-inferior compared to a licensed MenACWY plain polysaccharide vaccine (MenACWY-PS; MencevaxTM, GSK Vaccines, Belgium) in terms of Rabbit complement (rSBA) vaccine response to the four meningococcal serogroups one month after vaccination
The primary outcome of the study was met and results showing that a single dose of MenACWY-TT induced bactericidal antibodies which persisted in a majority of participants, and was well-tolerated up to 3 years post-vaccination were reported in a previous publication [30]
Summary
Long-term protection against meningococcal disease is associated with persistence of post-vaccination antibodies at protective levels. Neisseria meningitidis serogroups A, B, C, W, Y and X account for the majority of invasive meningococcal infections, which are associated with high morbidity and mortality rates [1,2,3]. There are both geographical and temporal variations in the distribution of these serogroups; these variations are potentially influenced by international travel patterns [1,2,3,4]. In the Philippines, serogroup A was responsible for an outbreak of meningococcal disease in 2004–2005 [8]. Serogroup A was responsible for an outbreak following the Hajj in 1987 [12], while serogroup W was predominant during outbreaks in 2000 and 2001 [4, 9, 12]
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