Better Meningitis Vaccine

Scientists have found a way to make the meningococcal meningitis vaccine more effective. They have discovered a way to alter a vaccine antigen, improving the effectiveness of vaccines for meningitis caused by Neisseria meningitidis. Meningitis is swelling of the membranes that cover the brain and spinal cord. The illness can be caused by either a virus or bacteria. The vaccine antigen in the study enhances the effectiveness of the vaccine for meningococcal meningitis (a bacterial infection) only.

Researchers at the Children's Hospital & Research Center Oakland and University of Massachusetts Medical Center began the study trying to stimulate human immune responses against the bacteria using what is known as a factor H-binding protein (fHbp). In the process, scientists discovered that a minor change to the make-up of fHbp vaccine makes it more effective. "This mutant antigen has just one amino acid difference between it and the fHbp in the current vaccines, but that difference means that it no longer binds to human fH, and that resulted in much higher protective responses," said Dr. Dan Granoff, Director of CHORI's Center for Immunobiology and Vaccine Development. Additionally, the mutation can be replicated in other vaccines to make them more effective as well.

Several bacteria cause bacterial meningitis, including Neisseria meningitides, Streptococcus pneumonia, and Haemophilus influenzae type b (Hib). The Hib vaccine is part of regularly scheduled childhood vaccines, and has drastically decreased the number of meningococcal meningitis caused by Hib. Neisseria meningitides is one of the leading causes of bacterial meningitis in the world. In addition to vaccines, meningococcal meningitis can be treated with antibiotics if caught early. The illness is diagnosed through use of a spinal tap. Untreated meningitis can cause brain damage, hearing loss, learning disabilities, or in about ten percent of cases, death. The illness is spread through the sharing of respiratory and throat secretions like saliva.

The spread of Neisseria meningitidis has the highest potential for a meningitis epidemic. In the meningitis belt of sub-Saharan Africa, stretching from Senegal in the west to Ethiopia in the east, epidemics occur in the dry season between December and June. "This deadly disease affects hundreds of thousands of children throughout the world. Almost no other infection can kill a previously healthy child as fast as the meningococcus," says Dr. Granoff.

The same technique using the genetic mutation can be applied not only for the meningococcal meningitis vaccine, but for other vaccines that utilize fHbp.

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