Objective: To assess the safety and immunogenicity of a bivalent serogroups A/C meningococcal oligosaccharide-protein conjugate vaccine compared with the licensed meningococcal polysaccharide vaccine.
Design: Randomized controlled trial.
Study Population: Ninety healthy 18- to 24-month-old children who were seen at a southern California Kaiser Permanente clinic.
Interventions: Vaccination with either the meningococcal conjugate vaccine (at 1 of 2 dosages) or the polysaccharide vaccine, with 2 doses given 2 months apart.
Main Outcome Measurements: Immune response to each vaccine dose as determined by measurement of serogroup-specific total antibodies by enzyme-linked immunosorbent assay (ELISA) and by assessment of serum bactericidal activity.
Results: Both vaccines appeared to be safe, and nearly all children responded with greater than 4-fold increases in antibody levels. The 2 dosages of the conjugate vaccine induced similar antibody responses; therefore, the data for the 2 conjugate vaccine groups were combined. Following 2 doses, ELISA antibody levels against group C meningococcus were significantly higher in conjugate vaccine recipients than in polysaccharide vaccine recipients (16.66 microg/mL vs. 8.31 microgm/mL; P<.001), but antibody levels against group A were not significantly different 22.75 microg/mL vs 21.24 microg/mL; P=.70). The serum bactericidal assays showed striking differences between the conjugate and polysaccharide vaccine groups. Geometric mean serum bactericidal titers were significantly higher in conjugate vaccine recipients (755.6 vs 37.6 for group A, P<.001; 3197.9 vs 11.4 for group C, P<.001).
Conclusions: The immune response induced by this meningococcal oligosaccharide-protein conjugate vaccine was qualitatively different from that induced by the polysaccharide vaccine, and the antibodies it elicited provided greater functional activity.
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Clin Microbiol Rev
January 2025
Department of Medicine, Division of Pulmonary/Allergy/Critical Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA.
SUMMARY (the "pneumococcus") is a significant human pathogen. The key determinant of pneumococcal fitness and virulence is its ability to produce a protective polysaccharide (PS) capsule, and anti-capsule antibodies mediate serotype-specific opsonophagocytic killing of bacteria. Notably, immunization with pneumococcal conjugate vaccines (PCVs) has effectively reduced the burden of disease caused by serotypes included in vaccines but has also spurred a relative upsurge in the prevalence of non-vaccine serotypes.
View Article and Find Full Text PDFExpert Rev Vaccines
December 2025
South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa.
Background: Due to high costs of pneumococcal conjugate vaccines (PCV), transitioning from a two (2 + 1) to a single dose (1 + 1) primary series with a booster should be considered. This study evaluated the immune response at 18 months of age following a 1 + 1 compared to a 2 + 1 schedule of 10-valent (PCV10) and 13-valent (PCV13) vaccines.
Research Design And Methods: A single-center, open-label, randomized trial conducted in Soweto, South Africa, evaluated the immunogenicity of differing dosing schedule for PCV10 and PCV13.
J Infect
January 2025
Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, United States.
Background: Pneumococcal conjugate vaccines (PCVs) introduced in childhood national immunization programs lowered vaccine-type invasive pneumococcal disease (IPD), but replacement with non-vaccine-types persisted throughout the PCV10/13 follow-up period. We assessed PCV10/13 impact on pneumococcal meningitis incidence globally.
Methods: The number of cases with serotyped pneumococci detected in cerebrospinal fluid and population denominators were obtained from surveillance sites globally.
J Infect Chemother
January 2025
Institute of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8576, Japan.
Introduction: We investigated clinical and microbiological characteristics of invasive Haemophilus influenzae disease (IHD) during recent 20 years in the Minami Ibaraki Area.
Methods: H. influenzae strains isolated from the blood and the cerebrospinal fluid in 5 hospitals located in this area between 2001 and 2020 (the pre-vaccination period [PreVP]: 2001-2010, the post-vaccination period [PostVP]: 2011-2020) were consecutively collected.
Zhonghua Yu Fang Yi Xue Za Zhi
January 2025
Immunization Program Institute of Shaanxi Provincial Center for Disease Control and Prevention, Xi'an 710054, China.
To investigate the safety of the tetravalent meningococcal conjugate vaccine (MPCV-ACYW) in combination with the inactivated poliomyelitis (IPV) vaccine and diphtheria-tetanus-acellular pertussis (DTaP) vaccine for infants aged 3-5 months and provide real-world evidence for the immunization strategy of vaccine combination. From June to October 2023, a total of 600 3-month-old infants were selected and divided into three groups: control group, mono-vaccination group and combined vaccination group. They were simultaneously or individually vaccinated with MPCV-ACYW, IPV and DTaP vaccines at 3, 4, and 5 months of age, respectively.
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