The U.S. Food and Drug Administration (FDA) last week approved a new vaccine called MCV4 (marketed as Menactra) that protects against four strains (A, C, Y, and W-135) of Neisseria meningitidis, the most common cause of meningitis in children and adolescents. The company that makes MCV4 already makes a similar polysaccharide vaccine against the same strains of bacteria (MPSV, Menomune); however, the new vaccine is a type of vaccine called a conjugate vaccine, which causes a stronger reaction by the immune system, resulting in better and longer lasting immunity. The new vaccine is expected to replace Menomune for use in adolescents and college students, who are at higher risk of this type of meningitis. The vaccine works so well that it is expected to become part of the official U.S. vaccine schedule. The vaccine has been approved for use in children ages 11 and up; the company is currently testing the vaccine in younger children, who are also at risk for this infection. It may eventually become part of the routine immunization schedule in younger children as well.
This form of meningitis is well-known to most people; it is what most people think of when they think of meningitis (though there are several causes of the disease, some of which are much less serious). Meningitis caused by Neisseria meningitidis often starts suddenly and rapidly progresses to death, sometimes before treatment can even be started. Those that do survive are often left with disabilities. The bacteria also causes blood infections which can be extremely serious or fatal.
Neither the new vaccine nor the older one protect against a strain of the bacteria called type B, which accounts for about 1/3 of cases. Developing a vaccine for this type has been extremely difficult, and scientists are continuing to try to develop a safe and effective vaccine against this strain as well.
