title: Effect of community-wide conjugate pneumococcal vaccine use in infancy on nasopharyngeal carriage through 3 years of age: a cross-sectional study in a high-risk population.
abstract: BACKGROUND
  A 7-valent pneumococcal conjugate vaccine (PnCRM7) has been shown to be highly effective in preventing invasive pneumococcal disease. Pneumococcal conjugate vaccines also protect against nasopharyngeal carriage of vaccine serotypes, but the duration of protection against nasopharyngeal carriage is not known.
  
  
  METHODS
  A group-randomized efficacy trial of PnCRM7 (vaccine serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F) was conducted on the Navajo and White Mountain Apache reservations from April 1997 to October 2000. A group C meningococcal conjugate vaccine was used as the control vaccine. Infants enrolled between 6 weeks and 7 months of age received 3 doses of vaccine 2 months apart and a fourth dose at 12-15 months of age. Vaccinees were enrolled in a nasopharyngeal carriage study from February 2001 to January 2002 to assess the duration of protection against pneumococcal carriage induced by PnCRM7.
  
  
  RESULTS
  We included 749 children in the analysis, including 468 children vaccinated with PnCRM7 and 281 children vaccinated with group C meningococcal conjugate vaccine. The median age was 3.3 years (range, 1-7 years), and the median time since last dose of study vaccine was 27 months (range, 12-48 months). Frequencies of overall pneumococcal carriage were similar among PnCRM7 and group C meningococcal conjugate vaccine recipients (63.9% vs. 60.5%, respectively). The absolute frequency of vaccine-type pneumococcal carriage was lower among PnCRM7 recipients (10.3%) than among controls (17.1%; P = .01). This reduction was offset by an increase of nonvaccine-type pneumococcal carriage among PnCRM7 recipients (39.2% vs. 29.8%; P = .01).
  
  
  CONCLUSIONS
  Community-wide PnCRM7 vaccination in infancy reduces the prevalence of vaccine-type carriage and increases the prevalence of nonvaccine-type carriage through at least 3 years of age.
authors.affiliation: Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Millar
authors.forename: Katherine L
authors.initials: KL
authors.lastname: O'Brien
authors.forename: James P
authors.initials: JP
authors.lastname: Watt
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Bronsdon
authors.forename: Jean
authors.initials: J
authors.lastname: Dallas
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Whitney
authors.forename: Raymond
authors.initials: R
authors.lastname: Reid
authors.forename: Mathuram
authors.initials: M
authors.lastname: Santosham
mesh_terms: D002353:Carrier State / Q000517:prevention & control; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000008:administration & dosage*; D009305:Nasopharynx / Q000382:microbiology; D011008:Pneumococcal Infections / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines