Temporal trends of invasive disease due to Streptococcus pneumoniae among children in the intermountain west: emergence of nonvaccine serogroups

Clin Infect Dis. 2005 Jul 1;41(1):21-9. doi: 10.1086/430604. Epub 2005 May 26.


Background: Use of the heptavalent pneumococcal conjugate vaccine (PCV-7 [Prevnar]) has been associated with decreased a incidence of invasive pneumococcal disease (IPD) among children in the United States.

Methods: Cases of IPD in children < 18 years of age insured by or receiving health care from Intermountain Health Care during 1996-2003 were identified. Isolates of S. pneumoniae from children with IPD treated at Primary Children's Medical Center (PCMC; Salt Lake City, UT) during 1997-2003 were serogrouped. Temporal trends of IPD, serogroup distribution of pneumococci, and antibiotic resistance among pneumococci were analyzed.

Results: A total of 1535 cases of IPD were identified. The rate of IPD decreased 27% after the introduction of PCV7. Among children with IPD who were cared for at PCMC, disease in 73% was caused by PCV7 serogroups in 1997-2000, compared with 50% in 2001-2003 (P < .001), and the percentage of isolates resistant to penicillin decreased from 34% in 1997-2000 to 22% in 2001-2003 (P = .04). The percentage of IPD cases that were empyema increased from 16% to 30% (P = .015), and the percentage of severe cases of IPD increased from 57% to 71% (P = .026). Children with IPD due to non-PCV7 serogroups were older, were more likely to have parapneumonic empyema, and had longer hospital stays.

Conclusions: The incidence of IPD in the IMW decreased by 27% after the introduction of the PCV7 vaccine. During the postvaccine period (2001-2003), there were significant decreases in the proportion of cases of IPD caused by PCV7 and antibiotic-resistant serogroups. These benefits were accompanied by a significant increase in the proportion of IPD cases due to non-PCV7 serogroups, with increases in the incidence of empyema and severe IPD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Drug Resistance, Bacterial
  • Female
  • Heptavalent Pneumococcal Conjugate Vaccine
  • Humans
  • Immunization Programs
  • Incidence
  • Infant
  • Male
  • Meningococcal Vaccines / administration & dosage*
  • Penicillin Resistance
  • Pneumococcal Infections / epidemiology*
  • Pneumococcal Infections / microbiology*
  • Pneumococcal Infections / prevention & control
  • Pneumococcal Vaccines / administration & dosage*
  • Population Surveillance
  • Serotyping
  • Streptococcus pneumoniae / classification*
  • Streptococcus pneumoniae / drug effects
  • Streptococcus pneumoniae / isolation & purification*
  • Utah / epidemiology
  • Vaccination
  • Vaccines, Conjugate / administration & dosage


  • Heptavalent Pneumococcal Conjugate Vaccine
  • Meningococcal Vaccines
  • Pneumococcal Vaccines
  • Vaccines, Conjugate