Prevalence of Occult Bacteremia in Children
Aged 3 to 36 Months Presenting to the
Emergency Department with Fever in the
Postpneumococcal Conjugate Vaccine Era
Matthew Wilkinson, MD, Blake Bulloch, MD, and Matthew Smith, MD
Objectives: The goal of this study was to identify the prevalence of occult bacteremia (OB) in well-
appearing, previously healthy children aged 3 to 36 months who present to the emergency department
(ED) with fever without source in the post–pneumococcal conjugate vaccine (PCV) era.
Methods: This was a retrospective cohort study of children presenting to an urban pediatric ED
between July 1, 2004, and June 30, 2007. Children were included if they were aged 3 to 36 months, feb-
rile, and previously healthy; had no source of infection on examination; had a blood culture drawn; and
were discharged from the ED. Outcome measures were rates of OB and contaminant rates.
Results: A total of 8,408 children met all inclusion criteria. There were 21 true-positives, yielding an OB
rate of 0.25% (95% confidence interval [CI] = 0.16% to 0.37%). There were 159 contaminant cultures
yielding a contaminant rate of 1.89% (95% CI = 1.61% to 2.19%), or a ratio of 7.6 contaminants for each
true-positive. There were 14 included patients who grew Streptococcus pneumoniae from the blood, for
a rate of 0.17% (95% CI = 0.09% to 0.27%).
Conclusions: Given the current rate of OB in the post-PCV era, it may no longer be cost-effective to
send blood cultures on well-appearing, previously healthy children aged 3 to 36 months who have fever
ACADEMIC EMERGENCY MEDICINE 2009; 16:220–225 ª 2008 by the Society for Academic Emergency
Keywords: bacteremia, fever, infant, emergency medicine, Streptococcus pneumoniae
36-month-old children presenting to an outpatient setting
with fever without a source (FWS), has been the subject
of increased scrutiny over the past few years as the intro-
duction of the pneumococcal conjugate vaccine (PCV) has
led to a dramatic decrease in the prevalence of occult
pneumococcal bacteremia. Guidelines published as far
he evaluation of well-appearing febrile children
has been an area of intense research and debate
for decades. A subset of these patients, 3- to
back as 2000 had recommended eliminating the workup
for occult bacteremia (OB) once an effective pneumococ-
cal vaccine had been widely utilized.1Authorities have
also suggested that the evaluation for OB would no
longer be necessary should the overall disease preva-
lence fall below 1%.1,2A cost-effectiveness analysis pub-
lished in 2001 concluded that no workup would be the
most cost-effective approach to febrile 3- to 36-month
children once the OB rate fell below 0.5%.3Several stud-
ies published using post-PCV data have suggested that
the prevalence of pneumococcal bacteremia in well-
appearing febrile children aged 3 to 36 months is cur-
rently in the range of 0.24% to 0.91% and that overall OB
prevalence in the same group is in the range of 0.65% to
0.91%.4–7Yet, despite published guidelines, expert opin-
ion, and published post-PCV immunization rates, studies
have shown that a large proportion of pediatric provid-
ers in ambulatory centers continue to evaluate these chil-
dren for OB by utilizing blood cultures.4–8Possible
reasons for this include a lack of a clear post-PCV fever
missed OB, and concerns about the sample sizes and
PII ISSN 1069-6563583
ª 2008 by the Society for Academic Emergency Medicine
From the Department of Emergency Medicine (MW, BB)
and the Department of Infectious Diseases (MS), Phoenix
Children’s Hospital, Phoenix, AZ.
Received August 12, 2008; revision received October 8, 2008;
accepted October 20, 2008.
Presented at the Pediatric Academic Society, Honolulu, HI, May
The authors have indicated they have no financial relationships
relevant to this article to disclose.
Address for correspondence and reprints: Blake Bulloch, MD;
A related commentary appears on page 258.
22. Stecher DS, Adelman R, Brinkman T, Bulloch B.
Accuracy of a state immunization registry in the
pediatric emergency department. Pediatr Emerg
Care. 2008; 24:71–4.
23. Goldstein KP, Kviz FJ, Daum RS. Accuracy of
immunization histories provided by adults accom-
panying preschool children to a pediatric emer-
gency department. JAMA. 1993; 270:2190–4.
24. Callahan JM, Reed D, Meguid V, Wojcik S, Reed K.
Utility of an immunization registry in a pediatric
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25. Centers for Disease Control and Prevention (CDC).
National, state, and local area vaccination coverage
among children aged 19-35 months–United States,
2006. MMWR Morb Mortal Wkly Rep. 2007; 56:880–5.
26. Centers for Disease Control and Prevention. 2006
Nov 2, 2008.
ACAD EMERG MED•March 2009, Vol. 16, No. 3•www.aemj.org