Invasive pneumococcal disease in Alaskan children: impact of the seven-valent pneumococcal conjugate vaccine and the role of water supply.
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.
Wenger
Jay D
JD
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
Zulz
Tammy
T
Bruden
Dana
D
Singleton
Rosalyn
R
Bruce
Michael G
MG
Bulkow
Lisa
L
Parks
Debbie
D
Rudolph
Karen
K
Hurlburt
Debby
D
Ritter
Troy
T
Klejka
Joseph
J
Hennessy
Thomas
T
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
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines