Decline in Invasive Pneumococcal Disease after the Introduction of Protein–Polysaccharide Conjugate Vaccine

In early 2000, a protein-polysaccharide conjugate vaccine targeting seven pneumococcal serotypes was licensed in the United States for use in young children.

We examined population-based data from the Active Bacterial Core Surveillance of the Centers for Disease Control and Prevention to evaluate changes in the burden of invasive disease, defined by isolation of Streptococcus pneumoniae from a normally sterile site. Serotyping and susceptibility testing of isolates were performed. We assessed trends using data from seven geographic areas with continuous participation from 1998 through 2001 (population, 16 million).