Meningococcal Serogroup B Vaccine Is Effective in Chile

Lara C. Pullen, PhD

January 18, 2012

January 18, 2012 — An adolescent 4-component meningococcal (4CMenB) vaccine appears to be effective when administered on a schedule of 2 doses from 1 to 6 months apart, according to a new study. María Elena Santolaya, MD, from the Department of Pediatrics, University of Chile, Santiago, and colleagues performed the study, which was published online January 18 in the Lancet.

The authors note in a news release that, "Development of a broadly protective vaccine against meningococcus B has been a longstanding challenge in order to provide more comprehensive protection against the most common pathogenic meningococcus. Currently this is the predominant strain in Europe and is a substantial contributor to the disease burden in the United States, in large part due to the control of other strains with effective MebC or MenACWY vaccine strategies. In this context, adding a meningococcal B vaccine as a standalone or eventually combined vaccine can be foreseen for both regions in the near future."

To develop broadly protective vaccines against serogroup B, whole-genome sequencing was used to identify proteins on the surface of many meningococcal strains. This pivotal study showed a potentially protective immune response against serotype B in almost 100% of vaccinated adolescents (a total of 1631 adolescents with a mean age of nearly 14 years), irrespective of previous antibody status. The vaccine was also found to be well-tolerated.

Protective human complement titres against 3 meningococcal serogroup B strains developed in from 92% to 97% of adolescents after 1 dose of 4CMenB vaccine and only 29% to 50% following placebo administration. Protective titres increased to from 99% to 100% after 2 or 3 doses were administered at 1-, 2-, or 6-month intervals. The high percentage of participants in the study with preexisting human complement titres against meningococcal test strains indicates environmental exposure.

The authors note that the actual level of protection will depend on geographical strain variation, as circulating meningococcal B strains are known to vary worldwide. Nonetheless, data on invasive strains of the disease circulating in Chile would suggest that 2 doses of 4CMenB given to healthy adolescents are protective against meningococcal serogroup B disease. Additional studies also have shown the vaccine to be effective in adults and children.

As the authors explain, safe and efficacious vaccines exist for protection against 4 of 6 of the major serogroups of Neissera meningitides, which cause meningococcal diseases, including meningitis. Because of the challenging immunogenic properties of serotype B, the latest vaccines that are either licensed or in the final stages of development only protect against the 4 major strains: serogroups A, C, W135, and Y. The ACWY vaccine is currently used in the United States to protect people against these 4 subtypes.

In an accompanying editorial, David S. Stephens, MD from Emory University School of Medicine and the VA Medical Center, Atlanta, Georgia, questions whether additional booster doses would be needed to maintain protection, and whether the vaccine could be targeted to infants and young children — a major group at risk for serogroup B disease. "Data are also needed for concurrent administration of 4CMenB with other vaccines," Dr. Stephens states, adding that answers to all of these questions "are crucial to widespread use and population-specific recommendations."

The study was funded by Novartis Vaccines and Diagnostics. Five of the coauthors are fulltime employees of Novartis Vaccines and Diagnostics. Dr. Stephens has disclosed no relevant financial relationships.

Lancet. Published online January 18, 2012. Abstract

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