Immunogenicity and Safety of a Meningococcal Quadrivalent Conjugate Vaccine in Saudi Arabian Adolescents Previously Vaccinated with One Dose of Bivalent and Quadrivalent Meningococcal Polysaccharide Vaccines: a Phase III, Controlled, Randomized, and Modified Blind-Observer Study

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>Reduced immune responses to repeated polysaccharide vaccination have been previously reported, but there are limited immunogenicity data on the use of meningococcal polysaccharide vaccine (PSV) followed by meningococcal conjugate vaccine. Saudi Arabian adolescents (aged 16 to 19 years) who had previously been vaccinated with ≥1 dose of bivalent meningococcal polysaccharide vaccine and 1 dose of quadrivalent meningococcal polysaccharide (MPSV4) were enrolled in a controlled, randomized, and modified observer-blind study (collectively termed the PSV-exposed group). The PSV-exposed group was randomized to receive either quadrivalent meningococcal conjugate vaccine (MCV4) (<jats:italic>n</jats:italic>= 145 PSV-exposed/MCV4 group) or MPSV4 (<jats:italic>n</jats:italic>= 142 PSV-exposed/MPSV4 group), and a PSV-naïve group received MCV4 (<jats:italic>n</jats:italic>= 163). Serum samples collected prevaccination and 28 days postvaccination were measured by baby rabbit serum bactericidal antibody (rSBA) assay, and vaccine tolerability and safety were also evaluated. For each serogroup, the postvaccination geometric mean titers (GMTs) were significantly higher in the PSV-naïve group than in either group comprised of the PSV-exposed participants. The postvaccination serogroup C rSBA GMT was significantly higher in the PSV-MCV4 group than in the PSV-MPSV4 group after adjusting for prevaccination GMTs. Although not statistically significant, similar differences were observed for serogroups A, Y, and W-135. No worrisome safety signals were detected. This study demonstrated MCV4 to be safe and immunogenic in those who had previously received polysaccharide vaccination, and it suggests that conjugate vaccine can partially compensate for the hyporesponsiveness seen with repeated doses of polysaccharide vaccine.</jats:p>

Different Long-Term Duration of Seroprotection against Neisseria meningitidis in Adolescents and Middle-Aged Adults after a Single Meningococcal ACWY Conjugate Vaccination in The Netherlands

“…This difference seems due to both significantly higher peak titers one month after vaccination for all three serogroups and a lower antibody decay rate for MenC and MenW in adolescents in the years thereafter. In former studies, adolescents showed a good immune response in reaction to a MenACWY-TT vaccination [ 14 , 19 , 20 , 21 , 29 , 48 , 49 ] and protection is known to last for at least several years [ 50 , 51 , 52 ]. Information about long-term protection in middle-aged adults is, however, scarce and the available studies had a short follow-up or investigated other conjugate vaccines or the plain polysaccharide vaccine [ 53 , 54 , 55 , 56 ].…”

“…To protect older age groups directly against IMD, vaccination of other age categories might be required [ 18 ]. In former studies, MenACWY-TT vaccination has shown to elicit a good immune response in both children and adults [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. However, we have previously shown that the functional antibody titers in middle-aged adults were lower compared to adolescents already at one month after vaccination [ 25 ].…”