NEW YORK (Reuters Health) - A conjugate vaccine against Streptococcus pneumoniae and group C Neisseria meningitidis elicits a lower immune response against N. meningitides than does the single component vaccine, results of a phase II clinical trial shows.
“These results highlight...the importance of assessing the immunogenicity of all coadministered vaccine antigens in prelicensure trials,” lead author Dr. Jim P. Buttery and colleagues emphasize in their report, published in the April 13th issue of the Journal of the American Medical Association.
Dr. Buttery, at the University of Melbourne in Parkville, Australia, and his team compared outcomes of administering monovalent group C meningococcal glycoconjugate vaccine (MenC) versus a combination 9-valent pneumococcal-group C meningococcal conjugate candidate vaccine (Pnc9-MenC).
Included were 120 infants in each group who received three doses of vaccine at ages 2, 3, and 4 months along with routine inoculations, including those against Haemophilus influenzae type b (Hib) and diphtheria.
When the subjects were tested at age 5 months, geometric mean titers against N. meningitidis were 179 in the Pcn9-MenC group versus 808 in the MenC group (p < 0.001). The percentage of infants in each group raising titers greater than 1:128 was 81% versus 94%, respectively.
Antibody responses to Hib and diphtheria were also reduced in the Pcn9-MenC group, although all infants were above the protective cutoff levels for both vaccines.
This study “illustrates the unpredictability of immunogenicity when combining multivalent vaccines, each immunogenic in separate form,” Dr. Buttery’s group points out.
“The Pcn9-MenC vaccine as tested may not be a suitable replacement for individual MenC or pneumococcal glycoconjugate vaccines,” they conclude.
This study was funded by Wyeth Vaccines.
Source: JAMA 2005;293:1751-1758. [ Google search on this article ]
MeSH Headings:Recombinant Proteins: Tetanus Toxoid: Vaccines, Synthetic: Diphtheria-Tetanus-Pertussis Vaccine: Vaccines, Combined: Haemophilus Vaccines: Vaccines, ConjugateCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
