ABSTRACT
Few infectious pathogens match the global impact of Streptococcus pneumoniae infections. In industrialized countries, S. pneumoniae is the most common identified bacterial cause of hospitalization for pneumonia, meningitis, and acute otitis media [1-3]. Invasive pneumococcal infections are most common among the very young (generally, 100-200 cases per 100,000 persons aged <2 years per year) and the elderly (45-90 per 100,000 persons aged >65 years per year) (Figure 1) [4-9]. Attack rates for persons aged 85 years and older are similar to those in infants [6]. These numbers translate into 106,000-175,000 hospitalizations and 7000-12,500 deaths in the United States annually [10]. Certain racial and ethnic groups, such as American Indians and Alaska Natives, are at increased risk for serious pneumococcal infections, as are individuals with underlying illnesses such as human immunodeficiency virus (HIV) [4,5,7-9,12,13].
