Epidemiology of invasive Streptococcus pneumoniae infections in the UnitedStates, 1995-1998 - Opportunities for prevention in the conjugate vaccine era

Context Pneumococcal polysaccharide Vaccine is recommended for elderly pers ons and adults with certain chronic illnesses. Additionally, a recently lic ensed pneumococcal 7-valent conjugate vaccine has been recommended for use in young children and could dramatically change the epidemiology of pneumoc occal disease. Objectives To assess pneumococcal disease burden in the United States, esti mate the potential impact of new vaccines, and identify gaps in vaccine rec ommendations, Design and Setting Analysis of data from the Active Bacterial Core Surveill ance (ABCs)/Emerging infections Program Network, an active, population-base d system in 9 states. Patients A total of 15860 cases of invasive pneumococcal disease occurring between January 1, 1995, and December 31, 1998, Main Outcome Measures Age- and race-specific pneumoccocal disease incidence rates per 100000 persons, case-fatality rates, and vaccine preventability. Results In 1998, overall incidence was 23.2 cases per 100000, corresponding to an estimated 62840 cases in the United States. Incidence was highest am ong children younger than 2 years (166.9) and adults aged 65 years or older (59.7). Incidence among blacks was 2.6 times higher than among whites (95% confidence interval [CI], 2,4-2.8). Overall, 28.6% of case-patients were a t least 65 years old and 85.9% of cases in this age group were due to serot ypes included in the 23-valent polysaccharide vaccine; 19.3% of case-patien ts were younger than 2 years and 82.2% of cases in this age group were due to serotypes included in the 7-valent conjugate vaccine. Among patients age d 2 to 64 years, 50.6% had a vaccine indication as defined by the Advisory Committee on Immunization Practices (ACIP), The case-fatality rate among pa tients aged 18 to 64 years with an ACIP indication was 12.1% compared with 5.4% for those without an indication (relative risk, 2.2; 95% CI, 1.7-2.9). Conclusions Young children, elderly persons, and black persons of ail ages are disproportionately affected by invasive pneumococcal disease. Current A CIP recommendations do not address a subset of persons aged 18 to 64 years but do include those at highest risk for death from invasive pneumococcal d isease.