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New Meningococcal A Conjugate Vaccine Is Effective

New vaccine elicits stronger group A antibody response than polysaccharide reference vaccine

WEDNESDAY, June 15 (HealthDay News) -- A new meningococcal A (MenA) conjugate vaccine (PsA-TT) has been found to have a stronger antibody response to group A meningococci than a quadrivalent polysaccharide reference vaccine (PsACWY), according to a study published in the June 16 issue of the New England Journal of Medicine.

Samba O. Sow, M.D., from the Centre pour le Développement des Vaccins in Bamako, Mali, and colleagues evaluated PsA-TT in two studies in Africa. In the first study (study A), 601 children, aged 12 to 23 months, were randomly assigned to receive PsA-TT, PsACWY, or a Haemophilus influenzae type b (Hib-TT) conjugate control vaccine. Ten months later, 589 of the original participants randomly received a booster dose consisting of a full dose of PsA-TT or Hib-TT, or a one-fifth dose of PsACWY. In the second study (study B), 900 patients, aged 2 through 29 years, were randomly assigned to receive PsA-TT or PsACWY. Immunogenicity was assessed by measuring the activity of group A serum bactericidal antibody (SBA).

The investigators found that the SBA titers were at least four times as high as at baseline in 96 and 78.2 percent of participants from the PsA-TT group in studies A and B, respectively; and in 63 and 46.2 percent of participants from the PsACWY group of studies A and B, respectively. In both studies the geometric mean SBA titers in PsA-TT groups were significantly higher than in the PsACWY groups. In study A, the PsA-TT group had higher antibody titers at 40 weeks and had obvious immunologic memory.

"The PsA-TT vaccine elicited a stronger response to group A antibody than the PsACWY vaccine," the authors write.

One study author disclosed financial relationships with the pharmaceutical industry.

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