Prevention of Infection with Neisseria meningitidis and Haemophilus influenzae Type b

Abstract

MENINGOCOCCAL DISEASE Background Since the first description by Vieusseux in 1805 of an epidemic of "cerebrospinal fever," physicians have been aware of the potential for spread of meningococcal disease. Numerous studies of military recruits in the United States documented conclusively nasopharyngeal acquisition of Neisseria meningitidis during the course of their basic training. In the military setting, attack rates as high as 46% have been reported for exposed susceptible individuals. In the United States, endemic meningococcal disease occurs in 3,000 to 5,000 persons yearly. Secondary cases occur with a frequency of 0.4% in the first month following disease in the index case. The risk to household contacts is approximately 2.2/1,000/yr; this risk is greatest in the week after the onset of illness in the index case but remains in excess of the endemic disease rate for at least 1 month. The risk of secondary meningococcal disease in household contacts (adults and children) of an index case is 1,000 times greater than that for the population as a whole. Carriage Versus Invasive Disease Household contacts, day care center contacts, and bunk mates (military installations) of an index case frequently are noted to have an increased rate of carriage of N meningitidis in the nasopharynx. It has been noted repeatedly that when the carriage rate of N meningitidis is high, invasive disease is more likely to occur.