Meningococcal Vaccines of the Future
Infection with Meningococci has sobering ramifications. Between 9 – 19% of patients require bone amputations or skin grafting or suffer hearing loss. And an additional 10% with this infection die. Now that pneumococcal and Haemophilus vaccines are effective and utilized, meningococcal disease is the leading cause of bacterial meningitis. Meningococcal serogroups B and C have traditionally been the cause most of the 3000 annual infections in the USA. Increasingly serogroup Y is a cause of up to one-third of disease. Children are most susceptible to meningococcal infection at ages 0-5 and again at ages 15-24 (especially those at ages 16-18 year olds living in college dormitories).
A polysaccharide vaccine is available in the USA that protects against 4 serogroups of Meningococci. It is licensed for use in children over age 2 years. It’s used to control outbreaks and to protect high-risk persons, including those with immune deficiencies, college students about to reside in dormitories, and military recruits. This vaccine’s effects wear off after a few years. Repeat doses of the vaccine are not advised because this could result in immune tolerance to polysaccharides.
A conjugate vaccine shows advantages because it can induce immunity for long periods of time and provide “herd immunity” by reducing carriage of meningococcal bacteria in the nasopharynx. In Europe and Canada, this vaccine is being used and has provided immunity for at least 4 years when given to children older than age 1-year. In the USA, a conjugate vaccine was licensed in January 2005 for children older than age 10-years (effective against 4 serotypes, but not type B). The vaccine is likely to cost up to $80/dose, and initially supplies will be limited. Recommended age and indications (who will get it) are yet to be worked out. Although this new vaccine will not be effective against Type B meningococcal disease, research on this serotype continues.
(Healy CM, Baker CJ. Concise Rev Pediatr Infect Dis 2005; 24(2):175-176)
Comment. We will keep you posted and publish specific recommendations for this new vaccine when they are released. —H.T.
