National Center for Biotechnology Information NCBI NLM MEDLINE humans pubmed abstract nih national institutes of health national library of medicine research support u.s. gov't adult adolescent aged middle aged united states / epidemiology Child Infant P.H.S. preschool Incidence Evaluation Study population surveillance vaccines serotyping pneumococcal infections / epidemiology* pneumococcal infections / prevention & control* pneumococcal infections / microbiology penicillin resistance streptococcus pneumoniae / classification streptococcus pneumoniae / isolation & purification pneumococcal vaccines* conjugate heptavalent pneumococcal conjugate vaccine streptococcus pneumoniae / drug effects pmid:12724479 doi:10.1056/nejmoa022823 cynthia g whitney monica m farley active bacterial core surveillance of the emerging infections program network meningococcal vaccines*