80. Prevention of laboratory-confirmed influenza pneumonia through vaccination: Preliminary results from the CDC Etiology of Pneumonia in the Community (EPIC) Study
Session: Oral Abstract Session: Influenza Vaccine - Clinical Impact and Vaccine Response
Thursday, October 3, 2013: 8:45 AM
Room: The Moscone Center: 200-212

Background: Few influenza vaccine effectiveness (VE) studies have focused on serious influenza-associated outcomes. We assessed the effectiveness of influenza vaccines in preventing influenza-associated community-acquired pneumonia (CAP) hospitalizations from Jan. 2010-Jun. 2012 using data from the prospective CDC EPIC study.

Methods: Patients hospitalized with CAP at four study sites were enrolled during three consecutive influenza seasons. Influenza infections were confirmed by reverse transcriptase-polymerase chain reaction performed on nose/throat swabs. Vaccination was assessed by self-report and verified through record review. The study was restricted to patients aged six months or older, with verified vaccination and influenza infection status and enrolled during influenza seasons (defined using CDC surveillance data). We estimated VE by comparing vaccination status between influenza-positive CAP cases and influenza-negative CAP controls using logistic regression models, controlling for demographics, high-risk conditions, season, site and time from disease onset. Sensitivity analyses included restriction to complete influenza seasons (2010-2012), CAP patients admitted within seven days of disease onset, and patients that were influenza-negative but positive for other respiratory viruses as controls. Subgroup analyses by age, site and season were also conducted.   

Results: Overall, 1524 CAP patients (30% of total enrolled) were eligible for the VE study. Median age was 2 years for children and 56 years for adults. Of 126 influenza-positive CAP cases, 28 (22%) were vaccinated compared with 596 (43%) of 1398 influenza-negative controls. The overall adjusted VE was 63% (95% confidence interval [CI], 42-77%). Stratified estimates were 75% (CI, 43-89%) for children (<18 years) and 45% (CI, 1-70%) for adults. Results from sensitivity analyses were consistent with the main findings. Results from subgroup analyses were also consistent with the main findings but had limited precision due to small numbers (Figure).

Conclusion: These preliminary findings suggest that influenza vaccination was associated with a 63% reduction in the risk of influenza-associated CAP hospitalizations. VE appeared higher among children than among adults.


Carlos G. Grijalva, MD, MPH1, Yuwei Zhu, MD, MS1, Derek J. Williams, MD, MPH1, Wesley H. Self, MD, MPH1, Krow Ampofo, MD2, Andrew Pavia, MD, FIDSA, FSHEA2, Chris Stockmann, MSc2, Jonathan A. Mccullers, MD3, Sandra R. Arnold, MD4, Richard G. Wunderink, MD5, Evan J. Anderson, MD6, Stephen Lindstrom, PhD7, Alicia Fry, MD, MPH7, Ivo Foppa, MD, ScD7, Lyn Finelli, DrPH, MS7, Anna M. Bramley, MPH7, Seema Jain, MD8, Marie Griffin, MD, MPH1 and Kathryn Edwards, MD, FIDSA1, (1)Vanderbilt University School of Medicine, Nashville, TN, (2)Department of Pediatrics, Division of Pediatric Infectious Diseases, University of Utah School of Medicine, Salt Lake City, UT, (3)St. Jude Children's Research Hospital, Memphis, TN, (4)Le Bonheur Children's Hospital, Memphis, TN, (5)Pulmonary and Critical Care, Northwestern University Feinberg School of Medicine, Chicago, IL, (6)Pediatrics and Medicine, Emory University School of Medicine, Atlanta, GA, (7)Centers for Disease Control and Prevention (CDC), Atlanta, GA, (8)Centers for Disease Control and Prevention, Atlanta, GA


C. G. Grijalva, None

Y. Zhu, None

D. J. Williams, None

W. H. Self, None

K. Ampofo, None

A. Pavia, None

C. Stockmann, None

J. A. Mccullers, None

S. R. Arnold, None

R. G. Wunderink, None

E. J. Anderson, None

S. Lindstrom, None

A. Fry, None

I. Foppa, None

L. Finelli, None

A. M. Bramley, None

S. Jain, None

M. Griffin, MedImmune: Grant Investigator, Research grant

K. Edwards, None

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