title: Incidence of occult bacteremia among highly febrile young children in the era of the pneumococcal conjugate vaccine: a study from a Children's Hospital Emergency Department and Urgent Care Center.
abstract: BACKGROUND
  The optimal diagnostic approach to and management of well-appearing, highly febrile young children has been a matter of debate owing to the possibility of clinically inapparent, or occult, bacteremia (OB). The most common causative organism of OB is Streptococcus pneumoniae. Universal immunization with a heptavalent pneumococcal conjugate vaccine (PCV7) has recently been implemented, but there are limited data on the impact of this vaccine on the incidence of OB.
  
  
  OBJECTIVE
  To evaluate the incidence of OB in the era of routine use of PCV7.
  
  
  METHODS
  We conducted a retrospective cohort study of highly febrile (temperature, 39 degrees C) children between the ages of 2 months and 36 months who had blood cultures performed in the emergency department or urgent care center between December 11, 2001, and March 5, 2003, and were discharged to home at the time of the initial visit.
  
  
  RESULTS
  Of 329 blood cultures obtained from children who met inclusion criteria and did not meet exclusion criteria, 3 (0.91%; 95% confidence interval, 0%-1.9%) yielded a pathogenic bacterium; all were S pneumoniae. Neither an elevated total white blood cell count, an elevated absolute neutrophil count, nor an increased percentage of bands was highly predictive of OB. Blood cultures positive for organisms were more commonly due to contaminants (4; 95% confidence interval, 0%-2.4%) than pathogens.
  
  
  CONCLUSIONS
  In the PCV7 era, OB is uncommon in highly febrile children 2 to 36 months of age. With continued use of PCV7, the routine practice of obtaining blood cultures and complete blood cell counts may no longer be indicated in previously healthy, well-appearing, highly febrile children 2 to 36 months of age, particularly those who have received at least 1 dose of PCV7.
authors.affiliation: Division of Infectious Diseases, Schneider Children's Hospital of the North Shore-Long Island Jewish Health System, Albert Einstein College of Medicine, New Hyde Park, NY 11040, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Stoll
authors.forename: Lorry G
authors.initials: LG
authors.lastname: Rubin
mesh_terms: D016470:Bacteremia / Q000453:epidemiology* / Q000517:prevention & control; D002669:Child Welfare; D002675:Child, Preschool; D015331:Cohort Studies; D004636:Emergency Service, Hospital / Q000592:standards; D005260:Female; D005334:Fever / Q000382:microbiology*; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D022401:Meningococcal Vaccines / Q000627:therapeutic use*; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000627:therapeutic use*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D018074:Vaccines, Conjugate / Q000627:therapeutic use*
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022401:Meningococcal Vaccines; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate