Abstract
BackgroundThe best strategy to protect individuals against meningococcal disease is to immunize against multiple serogroups. Immunogenicity, antibody persistence, and safety of the EU-licensed meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in healthy participants aged 11–55 years from the Philippines and Saudi Arabia.MethodsIn this phase IIb, open, controlled study, 500 participants were randomised (3:1) to receive one dose of MenACWY-TT or a licensed meningococcal polysaccharide vaccine (Men-PS). Functional antibody responses against meningococcal serogroups A, C, W-135, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA) at Month 0, Month 1, Year 1, Year 2, and Year 3. Vaccine response was defined as an rSBA titre ≥32 at Month 1 in participants who were seronegative (rSBA titre <8) pre-vaccination and as at least a four-fold increase in titre in participants who were seropositive pre-vaccination. Solicited symptoms were recorded up to Day 4, safety outcomes up to Month 6, and serious adverse events related to vaccination up to Year 3.ResultsPre-specified criteria for non-inferiority of MenACWY-TT versus Men-PS were met in terms of rSBA vaccine response and incidence of grade 3 general symptoms. At Month 1, 82.7%–96.3% of MenACWY-TT and 69.7%–91.7% in Men-PS recipients had a vaccine response for each serogroup. At Year 3, ≥99.1% and ≥92.9% of MenACWY-TT recipients retained rSBA titres ≥8 and ≥128, respectively, as compared to ≥86.7% and ≥80.0% in the Men-PS group. Both vaccines had a clinically acceptable safety profile, although injection site redness and swelling were more frequent in MenACWY-TT recipients.ConclusionsThese results suggest that MenACWY-TT could protect adolescents and adults against meningococcal disease up to three years post-vaccination.Trial registrationThis study is registered at http://www.clinicaltrials.gov/NCT00356369.
Highlights
The best strategy to protect individuals against meningococcal disease is to immunize against multiple serogroups
Study participants A total of 500 participants were enrolled and vaccinated in this study; 374 in the ACWY-TT group (225 in the 11–17 years age stratum and 149 in the 18–55 years age stratum) and 126 in the meningococcal polysaccharide vaccine (Men-PS) group (76 in the 11–17 years age stratum and 50 in the 18–55 years age stratum)
Immunogenicity Bactericidal antibodies Since the lower limit (LL) of the 95% Confidence interval (CI) on the difference between the ACWY-TT and the Men-PS groups in the percentage of participants with an rSBA vaccine response was above −12% for serogroups C, W-135, and Y and above −15% for serogroup A, the primary objective of noninferiority of the vaccine response induced by the MenACWY-TT vaccine over the MenACWY polysaccharide vaccine was met for each serogroup (Table 2)
Summary
The best strategy to protect individuals against meningococcal disease is to immunize against multiple serogroups. Most invasive meningococcal disease is caused by six of the 12 known serogroups, namely serogroups A, B, C, W-135, Y, and more recently X [2,3]. In the Philippines, an outbreak caused by serogroup A occurred in 2004–2005 [3,10]. An outbreak caused by serogroup A occurred in 1987 and an outbreak caused by serogroup W-135 was reported in 2000–2001 [12,13,14,15]. Pilgrims to the Hajj are at increased risk for infection because of overcrowding, shared living facilities, and close contact with people from various parts of the world, which are all known risk factors for meningococcal disease [13]
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