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Prior to the advent of Hemophilus influenza b (Hib) vaccine, Hib meningitis or invasive disease developed by age 5 in up to one in 200 children. Multinational experience indicates dramatic declines in Hib disease, which hopefully portends actual elimination. The current report assesses the epidemiologic evolution of bacterial meningitis throughout the lifespan in the United States.
In 1994 and 1995, surveillance for five invasive bacterial diseases (Neisseria meningitidis, H. influenza, group B streptococcus, Listeria monocytogenes, and Streptococcus pneumoniae) was performed in 22 counties (in Georgia, Tennessee, Maryland, and California) representing more than 10 million persons, approximately 4% of the U.S. population. Results were compared with previously obtained surveillance data from 1986. Based upon these data, calculations reflecting projected epidemiology in the U.S. population as a whole are made, as detailed below.
In 1995, an estimated 5755 cases of bacterial meningitis caused by the five reference pathogens occurred. When compared with the 12,920 cases occurring in 1986, this represents a 55% decrease. Attesting to the efficacy of Hib vaccination, the median age of bacterial meningitis patients increased from 15 months in 1986 to 25 years in 1995. Most of this epidemiologic shift has resulted from the 94% reduction in pediatric Hib meningitis.
The five study pathogens are responsible for at least 80% of all cases of bacterial meningitis. The very favorable effects of Hib immunization will hopefully be echoed by the development of equally effective vaccines for the other pathogens and increased use of existing vaccines (e.g., pneumococcal).
Schuchat A, et al. N Engl J Med 1997; 337:970-976.