SELECTED ARTICLES FROM THE RECENT LITERATURE 2005

12/6/05

Conjugate meningococcal vaccine effects

Summary
Background – Meningococcal (MC) infections represent a significant threat in adolescents and college students, particularly those living in close proximity to one another. There are concerns about the protective efficacy of the existent MC quadivalent (Groups A,C,Y and W-135) polysaccharide vaccine (PSV- 4).

Findings – Keyserling et al of Emory Univ in Atlanta, GA, compared the effects of: 1) a recently developed conjugate vaccine containing the polysaccharides of the 4 MC groups conjugated to diphtheria toxoid protein (MCV-4) and 2) the existent PSV-4 vaccine in 881 healthy subjects, ages 11-18 years.

They found that both MCV-4 and PSV-4 induced 4 fold rises in the serum levels of antibodies bactericidal for the 4 MC groups in 80-96% of subjects. However, in a 3 year follow-up, there was persistence of this serum bactericidal activity following the MCV-4 immunization but not after the PSV-4 injection. A booster response was demonstrated after a second injection of MCV-4 at this follow-up time.

Both MCV-4 and PSV-4 were generally well tolerated. Reactions (mostly mild) were more common after MCV-4 then after PSV-4 (69% vs 30%).

Reference
Arch Pediatr Adoles Med 2005;159:907-913

Editor's Comments
These findings are another example of the superior immunogenicity when bacterial polysaccharides are conjugated to a protein such as diphtheria toxoid. This greater persistence of bactericidal activity induced by MCV-4 could be very important in protecting adolescents living in groups and going off to college.

 

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