Vaccine for Deadly Childhood Infection in the Works
WebMD News Archive
The bacteria, called Neisseria meningitidis group B, is responsible for most cases in the U.S. of the life-threatening infectious diseases bacterial meningitis and septicemia, which occur most often in children and young adults.
"We have made such tremendous progress in the last year and a half that we should be able to start testing a vaccine in humans by 2001. The process has been moving so far, so fast and we want to keep the momentum," vaccine designer Rino Rappuoli, PhD, says in an interview with WebMD. He and colleagues from the Chiron Corp. in Siena, Italy, the Institute for Genomic Research in Rockville, Md., and Oxford University in England described the vaccine development process in two studies published in the March 10 issue of the journal Science.
Bacterial meningitis (not to be confused with the less serious viral meningitis) is an inflammation of the membranes that surround the brain and spinal cord. It starts as a flu-like infection or sore throat, but within 24-48 hours after the first symptoms appear, it develops into a full-blown disease with severe headache, a stiff neck, vomiting, fever, mental confusion, and, in some cases, coma or death.
Septicemia, also called blood poisoning or bacteremia, is the presence of bacterial infection in the bloodstream, marked by frequent and intermittent high fever, shaking, and chills. In severe cases, the bloodstream can carry bacteria to the brain, liver, or other organs. Both bacterial meningitis and septicemia can be fatal unless patients get immediate hospitalization and intensive treatment with antibiotics.
Many people (by some estimates, as many as 30%) are infected with the bacteria that cause meningitis, which live in the throat without harming their human host. But for unknown reasons, in a small percentage of people who harbor the bacteria, it enters the bloodstream, crosses the blood-brain barrier that normally protects the brain from infections, and sets up shop, rapidly multiplying and causing the body to respond with an immune defense that causes the severe inflammation and other symptoms associated with the disease.
Although vaccines are available to protect adults -- but not children -- from the devastating effects of meningitis caused by other forms of the bacteria, group B meningitis strains have proved elusive. Vaccines work by raising the body's natural antibodies to a protein or other feature that lies on the surface of the invader (in this case, a bacteria). The antibodies then move through the bloodstream looking for a specific intruder, using that identifying protein -- much in the way that a beat cop will memorize the photo of a wanted criminal. But group B meningitis strains are shape-shifters that keep changing their appearance to evade capture by the immune system.