title: Invasive pneumococcal disease in Alaskan children: impact of the seven-valent pneumococcal conjugate vaccine and the role of water supply.
abstract: BACKGROUND
  Alaska Native (AN) children, especially those in the Yukon-Kuskokwim region (YK-AN children), suffer some of the highest rates of invasive pneumococcal disease (IPD) in the world. Rates of IPD declined after statewide introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in 2001, but increased in subsequent years.
  
  
  METHODS
  Population-based laboratory surveillance data (1986-2007) for invasive Streptococcus pneumoniae infection in Alaskan children <5 years old were used to evaluate the association of IPD rates and serotype distribution with immunization, socioeconomic status, and in-home water service.
  
  
  RESULTS
  Introduction of PCV7 vaccine resulted in elimination of IPD caused by vaccine serotypes, but was followed by increasing rates of IPD caused by nonvaccine serotypes. Among YK-AN children IPD rates dropped by 60%, but then rose due to non-PCV7 serotypes to levels 5- to 10-fold higher than rates in non-YK-AN children and non-AN children. IPD rates in YK-AN children were twice as high in villages where <10% of houses had in-home piped water compared with villages where more than 80% of houses had in-home piped water (390 cases/100,000 vs. 146 cases/100,000, P = 0.008).
  
  
  CONCLUSIONS
  High IPD rates in Alaska are associated with lack of in-home piped water (controlling for household crowding and per capita income). The effect of in-home piped water is most likely mediated through reduced water supply leading to limitations on handwashing.
authors: Arctic Investigations Program, National Center for Preparedness, Detection and Control of Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, Alaska 99508, USA. jdw2@cdc.gov
authors: Jay D
authors: JD
authors: Wenger
authors: Tammy
authors: T
authors: Zulz
authors: Dana
authors: D
authors: Bruden
authors: Rosalyn
authors: R
authors: Singleton
authors: Michael G
authors: MG
authors: Bruce
authors: Lisa
authors: L
authors: Bulkow
authors: Debbie
authors: D
authors: Parks
authors: Karen
authors: K
authors: Rudolph
authors: Debby
authors: D
authors: Hurlburt
authors: Troy
authors: T
authors: Ritter
authors: Joseph
authors: J
authors: Klejka
authors: Thomas
authors: T
authors: Hennessy
mesh_terms: D000413:Alaska / Q000453:epidemiology; D002675:Child, Preschool; D005260:Female; D006235:Hand Disinfection; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011008:Pneumococcal Infections / Q000453:epidemiology*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D012703:Serotyping; D012959:Socioeconomic Factors; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000276:immunology / Q000302:isolation & purification*; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines