Trends in invasive pneumococcal disease-associated hospitalizations

Abstract

Background: The heptavalent pneumococcal conjugate vaccine was licensed in the United States in 2000 for use in infants and children. Postlicensure surveillance revealed substantial regional and national decreases in invasive pneumococcal disease. It is not known whether widespread vaccine use has led to a concomitant decrease in invasive pneumococcal disease-associated hospitalization rates.

Objective: We examined national trends in rates of hospitalization among both children and adults with invasive pneumococcal disease.

Methods: Data from the 1998-2003 National Hospital Discharge Survey and population estimates from the National Center for Health Statistics were used to calculate rates of hospital discharge for patients admitted with invasive pneumococcal disease, defined as meningitis or bacteremia caused by Streptococcus pneumoniae.

Results: Rates of hospital discharge for patients admitted with invasive pneumococcal disease decreased during the study period from a peak of 12.03 discharges per 100,000 population in 1999 to 5.60 discharges per 100,000 population in 2003 (P < .001). Rates of hospital discharge for persons admitted with pneumococcal meningitis decreased from 1.60 discharges per 100,000 person-years in the prelicensure period to 0.53 discharges per 100,000 person-years in the postlicensure period. For persons > or = 65 years of age but not for those < 4 years of age, the rates of hospital discharge for those admitted with pneumococcal bacteremia were significantly lower during the postlicensure period, compared with the prelicensure period.

Conclusions: Hospital discharge rates for persons admitted with invasive pneumococcal disease, including meningitis, have decreased since introduction of the heptavalent pneumococcal conjugate vaccine. The decrease was driven in part by the reduction of invasive pneumococcal disease-associated hospitalizations in the subgroup aged > or = 65 years.