title: Effect of pneumococcal conjugate vaccine on pneumococcal meningitis.
abstract: BACKGROUND
  Invasive pneumococcal disease declined among children and adults after the introduction of the pediatric heptavalent pneumococcal conjugate vaccine (PCV7) in 2000, but its effect on pneumococcal meningitis is unclear.
  
  
  METHODS
  We examined trends in pneumococcal meningitis from 1998 through 2005 using active, population-based surveillance data from eight sites in the United States. Isolates were grouped into PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F), PCV7-related serotypes (6A, 9A, 9L, 9N, 18A, 18B, 18F, 19B, 19C, 23A, and 23B), and non-PCV7 serotypes (all others). Changes in the incidence of pneumococcal meningitis were assessed against baseline values from 1998-1999.
  
  
  RESULTS
  We identified 1379 cases of pneumococcal meningitis. The incidence declined from 1.13 cases to 0.79 case per 100,000 persons between 1998-1999 and 2004-2005 (a 30.1% decline, P<0.001). Among persons younger than 2 years of age and those 65 years of age or older, the incidence decreased during the study period by 64.0% and 54.0%, respectively (P<0.001 for both groups). Rates of PCV7-serotype meningitis declined from 0.66 case to 0.18 case (a 73.3% decline, P<0.001) among patients of all ages. Although rates of PCV7-related-serotype disease decreased by 32.1% (P=0.08), rates of non-PCV7-serotype disease increased from 0.32 to 0.51 (an increase of 60.5%, P<0.001). The percentages of cases from non-PCV7 serotypes 19A, 22F, and 35B each increased significantly during the study period. On average, 27.8% of isolates were nonsusceptible to penicillin, but fewer isolates were nonsusceptible to chloramphenicol (5.7%), meropenem (16.6%), and cefotaxime (11.8%). The proportion of penicillin-nonsusceptible isolates decreased between 1998 and 2003 (from 32.0% to 19.4%, P=0.01) but increased between 2003 and 2005 (from 19.4% to 30.1%, P=0.03).
  
  
  CONCLUSIONS
  Rates of pneumococcal meningitis have decreased among children and adults since PCV7 was introduced. Although the overall effect of the vaccine remains substantial, a recent increase in meningitis caused by non-PCV7 serotypes, including strains nonsusceptible to antibiotics, is a concern.
authors.affiliation: University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Heather E
authors.initials: HE
authors.lastname: Hsu
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Shutt
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Moore
authors.forename: Bernard W
authors.initials: BW
authors.lastname: Beall
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Bennett
authors.forename: Allen S
authors.initials: AS
authors.lastname: Craig
authors.forename: Monica M
authors.initials: MM
authors.lastname: Farley
authors.forename: James H
authors.initials: JH
authors.lastname: Jorgensen
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Lexau
authors.forename: Susan
authors.initials: S
authors.lastname: Petit
authors.forename: Arthur
authors.initials: A
authors.lastname: Reingold
authors.forename: William
authors.initials: W
authors.lastname: Schaffner
authors.forename: Ann
authors.initials: A
authors.lastname: Thomas
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Whitney
authors.forename: Lee H
authors.initials: LH
authors.lastname: Harrison
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008586:Meningitis, Pneumococcal / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D022242:Pneumococcal Vaccines; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects; D014481:United States / Q000453:epidemiology; D018074:Vaccines, Conjugate; D055815:Young Adult
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate