Protecting Against Serogroup B Meningococcal Strains - New Vaccine Shows Promise

Date: May-10-2012Serogroup B Meningococcal Strains - New Vaccine Shows Promise

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Main Category: Infectious Diseases / Bacteria / Viruses

Also Included In: Immune System / Vaccines

Article Date: 10 May 2012 - 12:00 PDT

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'Protecting Against Serogroup B Meningococcal Strains - New Vaccine Shows Promise'


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Serogroup B meningococcal strains have become the major cause of bacterial meningitis in many European and North American regions. A new study published Online First in The Lancet Infectious Diseases reveals that researchers are now one step closer to finding a vaccine that protects against a broad range of serogroup B meningococcal strains.

According to the phase II trial, the new vaccine for serogroup B Neisseria meningitidis proved safe and immunogenic in adolescents. Most adolescents produced bacterial antibodies that were active against 90% of the meningococcus sergroup B strains that occur in Europe and in the U.S.

Leading researcher Peter Richmond from the University of Western Australia School of Pediatrics and Child Health explains:

"Our data suggest that this vaccine is a promising and broadly protective meningococcal serogroup B vaccine candidate...If additional studies show similar immunogenicity and tolerability, this vaccine might help to reduce the global burden of invasive meningococcal disease."

Even though Cuba and New Zealand have developed vaccines specific to meningococcal serogroup B strains, developing a wide-spectrum protective vaccine has proved a challenge, because the proteins on the surface of these bacteria, against which an immune response is generated, can vary. This creates obstacles in developing a vaccine that is effective against many different strains.

The new bivalent recombinant vaccine named Lipoprotein 2086 consists of two variants of an antigen, which occur in at least 98% of all meningococcal serogroup B strains. To test the Lipoprotein 2086 vaccine's safety and its ability to produce an immune response (immunogenicity), the researchers conducted a randomized multi-center phase II trial that involved 539 healthy adolescents from 25 sites across Australia, Poland and Spain as adolescents have a higher risk of meningococcal infection.

The participants randomly received either three doses of the Lipoprotein 2086 vaccine (60 µg, 120 µg, or 200 µg of total protein) or placebo at 0, 2 and 6 months. To detect protective antibody responses against a panel of eight diverse serogroup B strains, the researchers measured immunogenicity with serum bactericidal assays using human complement (hSBA), which demonstrated that the three doses of vaccine proved successful in producing an immune response that indicated protection in 80 to 100% of adolescents.

Overall, each dosing group was observed to tolerate the vaccine well, with the most commonly reported side effect being mild-to-moderate pain at the injection site. The researchers note that after the third 200 µg dose, one serious vaccine-related adverse event occurred.

The researchers conclude:

"The high protection indicated by hSBA response to all test strains...suggests that bivalent recombinant lipoprotein 2086 is a broadly protective vaccine and that three doses is sufficient to confer high seroprotection...Future research will define the reactogenicity [the capacity of a vaccine to produce adverse reactions], breadth of coverage, and robustness of immunological protection afforded by the vaccine."

Muhamed-Kheir Taha and Ala Eddine Deghmane from the Paris Institut Pasteur in France wrote in a linked comment:

"Surveillance of meningococcal isolates and typing should continue and include sequencing of genes that encode factor H binding protein to monitor the emergence or expansion of any escape variants."



Written By Petra Rattue

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