Incidence of invasive pneumococcal disease among children after introduction of a 7-valent pneumococcal conjugate vaccine: a population-based study in Olmsted County, Minnesota.
To examine the effect of the 7-valent pneumococcal conjugate vaccine in a well-characterized population in Olmsted County, Minnesota, with a combination of urban and rural residents likely to have a relatively low risk of invasive pneumococcal disease (IPD).



This population-based study analyzed data from children younger than 5 years to determine the incidence of IPD from January 1, 1995, to December 31, 2007.



From 1995 through 2007, 29 cases of IPD were identified in the study population, but 2 patients denied research authorization; thus, 27 cases were available for review. From 1995-1999 to 2001-2003, the incidence of IPD decreased from 33.5 (95% confidence interval [CI], 16.6-50.5) to 10.8 (95% CI, 0.0-23.0) cases per 100,000 person-years (68% decrease; P=.046). The incidence subsequently increased to 15.2 (95% CI, 3.0-27.4) cases per 100,000 person-years from 2004 through 2007; however this change was not significant (P=.62). All cases of IPD with available serotype data from 2002 through 2007 (n=5) were due to non-7-valent conjugate vaccine serotypes.



Although the baseline incidence of IPD was much lower than that reported in other populations, the overall incidence of IPD decreased significantly in children younger than 5 years after introduction of a 7-valent conjugate vaccine.
Division of Infectious Diseases, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Cooper University Hospital, Camden, NJ 08103, USA. tsigrelis.constantine@yahoo.com
Constantine
C
Tsigrelis
Imad M
IM
Tleyjeh
W Charles
WC
Huskins
Brian D
BD
Lahr
Lisa M
LM
Nyre
Abinash
A
Virk
Larry M
LM
Baddour
D000367:Age Factors; D002675:Child, Preschool; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008910:Minnesota; D010406:Penicillins / Q000627:therapeutic use; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control; D022242:Pneumococcal Vaccines; D012189:Retrospective Studies; D012423:Rural Health; D014504:Urban Health; D018074:Vaccines, Conjugate
D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D010406:Penicillins; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate