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Publications (2)7.06 Total impact

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    ABSTRACT: One dose of a quadrivalent meningococcal conjugate (MC-4) vaccine elicits higher group C bactericidal responses in 2-year olds than a U.S.-licensed quadrivalent polysaccharide (MPS-4) vaccine [Granoff DM, Harris SL. Protective activity of group C anticapsular antibodies elicited in 2-year olds by an investigational quadrivalent Neisseria meningitidis-diptheria toxoid conjugate vaccine. Pediatr Infect Dis J, 2004;23:490-7]. Assess immunogenicity and persistence of serum antibody to capsular groups A, Y and W-135 in 2-year old children immunized with MC-4 vaccine. Measurement of antibody responses in sera from a multicenter randomized trial comparing MC-4 and MPS-4 vaccines. At 1 month, the group A serum bactericidal GMT was higher in the MC-4 than the MPS-4 group (P < 0.001) but there were no significant differences at 6 months. At 6 months, the respective Y and W-135 GMTs were higher in the MC-4 group (P < 0.05) but there were no differences at 1 month. The higher W-135 bactericidal titers reflected higher antibody avidity in the MC-4 group (P < 0.0001) and avidity maturation between 1 and 6 months (P < 0.05). At 2-year post-vaccination, the proportion of MC-4 immunized children with bactericidal titers > or =1:4 (presumed to be protective) was 15.0% (group A), 32.5% (group Y) and 45% (group W-135), as compared with 2.5, 15.4 and 17.5%, respectively, in unvaccinated children (P < 0.01 for group W-135; P < 0.05 for group A, and P = 0.07 for Y). One dose of the MC-4 vaccine in 2-year olds elicits higher A, Y and W-135 bactericidal titers than MPS-4 vaccine. Compared with unvaccinated children, serum antibody titers remain elevated for 2 years after MC-4 vaccination. However, many vaccinated children have titers <1:4 and may require a booster dose for sustained protection.
    Vaccine 07/2005; 23(34):4307-14. · 3.49 Impact Factor
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    ABSTRACT: An investigational quadrivalent (A, C, Y and W-135) meningococcal conjugate (MC-4) vaccine was reported to be more immunogenic in 2-year-olds than the currently licensed meningococcal polysaccharide vaccine, but persistence of serum antibody beyond 6 months after conjugate vaccination is unknown. Determine persistence and the immunologic basis of protective activity of group C anticapsular antibodies in sera obtained 2-3 years after MC-4 vaccination. Group C antibody concentrations, bactericidal activity and passive protective activity were measured in sera from 48 children, ages 4-5 years, who had been immunized 2-3 years earlier with an MC-4 vaccine and from 47 children who had not been previously vaccinated. Serum antibody concentrations were higher in the vaccinated than the unvaccinated children (geometric means, 0.30 and 0.09 mug/mL, respectively, P < 0.0001). Bactericidal titers > or =1/4 (considered protective) were infrequent in both vaccinated and unvaccinated children (14.6 and 6.4%, respectively, P = 0.3). Passive protective activity against bacteremia in the infant rat model was more frequent in sera from vaccinated (37.5%) than sera from unvaccinated children (12.5%, P < 0.02). The proportion of sera with passive protective activity increased with increasing anticapsular antibody concentrations (P < 0.0001). Serum group C antibody concentrations remained elevated for 2-3 years after MC-4 vaccination, and passive protective activity was more frequent in vaccinated than unvaccinated children. However, serum antibody concentrations in many vaccinated children were no longer sufficient to activate complement-mediated bacteriolysis in vitro or to confer passive protection against experimental group C disease.
    The Pediatric Infectious Disease Journal 03/2005; 24(2):132-6. · 3.57 Impact Factor