title: Geographic variation in invasive pneumococcal disease following pneumococcal conjugate vaccine introduction in the United States.
abstract: BACKGROUND
  Rates of invasive pneumococcal disease (IPD) varied among the United States before pneumococcal conjugate vaccine (PCV7) introduction. We compared trends in IPD rates among diverse US sites over 10 years since PCV7 introduction.
  
  
  METHODS
  Patients with IPD of all ages were identified through active population and laboratory-based surveillance in 8 geographic areas under continuous surveillance during 1998-2009. Isolates were serotyped. IPD incidence rates and percent changes were calculated by site, serotype group, age, and year.
  
  
  RESULTS
  Reductions in rates of IPD ranged, by site, from 19 to 29.9 cases per 100,000 population during 1998-1999 to 11.2-18.0 cases per 100,000 population during 2009 (rate reduction, 5.1-15.3 cases per 100,000 population). Reductions in IPD rates among children aged <5 years ranged from 35.7 to 117.2 cases per 100,000 population across the sites. Reductions in rates of IPD due to PCV7 serotypes were seen in all age groups at all sites, ranging from 12 to 21.4 cases per 100,000 population during 1998-1999 to <2 cases per 100,000 population during 2009 (92%-98% reductions). Serotype 19A rates ranged from 0.4 to 1.5 cases per 100,000 population during 1998-1999 to 1.3 to 3.4 cases per 100,000 population during 2009 (rate difference, 0.9-2.8 cases per 100,000 population); modest increases were observed for most age groups across the sites. Rates of IPD due to all other serotypes ranged from 6.3 to 10.3 cases per 100,000 population during 1998-1999 to 8.3-13.6 cases per 100,000 population during 2009 (rate difference, -0.4 to 5.7 cases per 100,000 population). Across the sites, the greatest rate increases were seen in the 50-64 and >65 year age groups.
  
  
  CONCLUSIONS
  Reductions in IPD due to vaccine serotypes were consistent across sites. Changes in serotype 19A and all other serotypes were variable. Although relative increases in non-vaccine type serotypes were large in some sites, absolute rate increases were small.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA. jrosen4@health.nyc.gov
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Rosen
authors.forename: Ann R
authors.initials: AR
authors.lastname: Thomas
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Lexau
authors.forename: Art
authors.initials: A
authors.lastname: Reingold
authors.forename: Jim L
authors.initials: JL
authors.lastname: Hadler
authors.forename: Lee H
authors.initials: LH
authors.lastname: Harrison
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Bennett
authors.forename: William
authors.initials: W
authors.lastname: Schaffner
authors.forename: Monica M
authors.initials: MM
authors.lastname: Farley
authors.forename: Bernard W
authors.initials: BW
authors.lastname: Beall
authors.forename: Matt R
authors.initials: MR
authors.lastname: Moore
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D005843:Geography; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000302:isolation & purification*; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines