Meningococcal vaccines show improved efficacy but still problematic

ATLANTA — Meningococcal conjugate vaccines have been effective in reducing illness in the United Kingdom for the past decade, but waning immunity is becoming more problematic, according to a speaker at the 2010 International Conference on Emerging Infectious Diseases.

The changing epidemiology of meningococcal serogroups A, B, C and Y is forcing the need for new vaccines and new vaccine delivery strategies, according to David Stephens, MD, vice president for research at the Robert W. Woodruff Health Sciences Center and Stephen W. Schwarzmann Distinguished Professor of Medicine at Emory University.

The meningococcal polysaccharide vaccines, which include serogroups A, C, Y and W-135, have been in use since the 1970s, Stephens said, and are safe and effective, with some efficacy rates at more than 85% in older children and adults. Immunogenicity, however, has been a weakness of these vaccines, especially in children younger than 24 months.

To address the issue of waning immunity, the Advisory Committee on Immunization Practices recommends that people aged 2 to 55 years who are at increased risk for meningococcal disease — including those with component deficiencies or asplenia, laboratory workers exposed to meningococcus or frequent travelers to meningococcal endemic areas — should receive a meningococcal conjugate booster.

But other solutions, besides booster doses, are needed.

During the past decade, meningococcal protein-polysaccharide conjugate vaccines have also been used with great success, according to Stephens. He said these vaccines have better immunological memory and booster effect with repeated doses, and these vaccines provide equal efficacy in terms of immune correlates, prevention in expanded populations and anticipation of a longer duration of protection.

Researchers are also in the process of developing new serogroup B vaccines, which Stephens said would be beneficial for Europe, Asia, the United States and South America, where this strain is predominant.

At a press conference yesterday, the NFID presented an overview of facts on meningitis and discussed updates to their S.T.O.P. Meningitis program. Visit their website to download valuable resources, including clipboard notes, coding information and customizable tools for educating adolescents and parents on the importance of meningococcal vaccination. – by Melissa Foster

For more information:

Stephens D. H4. Presented at: 2010 International Conference on Emerging Infectious Diseases; July 11-14, 2010; Atlanta.

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