Meningitis is an infection of the membranes (meninges) surrounding the brain and spinal cord. Although this disease is rare (only 2,800 Americans are affected annually) meningitis is fatal in approximately 10 and 13 percent of all cases. Another 10 percent develops serious health problems, including mental retardation, hearing loss and gangrene serious enough to require amputation of an arm or leg. In the 1990s, surveys conducted by the U.S. Centers for Disease Control and Prevention showed that college freshmen living in dormitories are at a slightly increased risk, and since then, many colleges and universities have been recommending (or requiring) that freshmen be vaccinated against the disease.
Meningitis can be caused by a viral (viral meningitis) or bacterial (bacterial meningitis) infection. The viral variety usually isn't serious and runs its course uneventfully, typically in about two weeks without treatment. The bacterial type is more dangerous. Early symptoms, which may develop over several hours or several days, can include high fever, headache and a stiff neck, nausea, vomiting, confusion, sleepiness and, eventually, seizures. Although many different kinds of bacteria can cause meningitis, the one most frequently responsible for this potentially disastrous illness is Neisseria meningitides, or menigococcus. It can be spread by kissing; sharing eating utensils, cigarettes or drinking glasses; or from droplets spread by a cough or sneeze.
The available vaccine offers 85- to 95-percent protection against four bacterial strains that are responsible for 70 percent of meningococcal disease in the United States, but not against the strains responsible for the remaining 30 percent. Immunity lasts for three to five years. Even if you are immunized, should you be exposed to meningococcal meningitis afterward, you'll need prompt preventive antibiotic treatment as a precaution against the possibility that the case was due to a strain the vaccine doesn't protect against.
The vaccine's side effects are minimal: some swelling and redness at the injection site and, rarely, flu-like symptoms or (even more rare) an allergic reaction. If you have had reactions to other vaccines, be sure to talk to your doctor about the risk you may face this time.
Andrew Weil, M.D.