Does Influenza Vaccination Modify Influenza Severity? Data on Older Adults Hospitalized With Influenza During the 2012-2013 Season in the United States

• Type of Material: Article
• Authors: Carmen S. Arriola, Emory University; Evan Anderson, Emory University; Joan Baumbach, New Mexico Department of Health; Nancy Bennett, University of Rochester; Susan Bohm, Michigan Department of Community Health; Mary Hill, Salt Lake City County Health Department; Mary Lou Lindegren, Vanderbilt University; Krista Lung, Ohio Department of Health; James Meek, Yale University; Elizabeth Mermel, Rhode Island Department of Health; Lisa Miller, Colorado Department of Public Health and Environment; Maya L. Monroe, Maryland Department of Health and Mental Hygiene; Craig Morin, Minnesota Department of Health; Oluwakemi Oni, Iowa Department of Public Health; Arthur Reingold, California Emerging Infections Program; William Schaffner, Vanderbilt University; Ann Thomas, Oregon Public Health Division; Shelley M. Zansky, New York State Department of Health; Lyn Finelli, Emory University; Sandra S. Chaves, Emory University
• Language: English
• Date: 2015-10-15
• Publisher: OXFORD UNIV PRESS INC
• Publication Version: Final Published Version
• Copyright Statement: © Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015.
• License: Creative Commons Universal : Public Domain Dedication
• Final Published Version (URL): http://dx.doi.org/10.1093/infdis/jiv200
• Title of Journal or Parent Work: JOURNAL OF INFECTIOUS DISEASES
• Volume: 212
• Issue: 8
• Start Page: 1200
• End Page: 1208
• Grant/Funding Information: This work was supported by the CDC (cooperative agreements CDC-RFA-CK12-1202 and 5U38HM000414).
• Keywords: severe illness; influenza; RISK; Infectious Diseases; adults; OUTCOMES; Science & Technology; DIAGNOSTIC-TESTS; OSELTAMIVIR; CHARLSON COMORBIDITY INDEX; influenza vaccine; LABORATORY-CONFIRMED INFLUENZA; RESPIRATORY SYNCYTIAL VIRUS; Microbiology; MORTALITY BENEFITS; Immunology; Life Sciences & Biomedicine; DISEASE; PROPENSITY SCORES
• Research Categories: Health Sciences, Immunology; Health Sciences, Public Health

Abstract

Background.Some studies suggest that influenza vaccination might be protective against severe influenza outcomes in vaccinated persons who become infected. We used data from a large surveillance network to further investigate the effect of influenza vaccination on influenza severity in adults aged ≥50 years who were hospitalized with laboratory-confirmed influenza. Methods.We analyzed influenza vaccination and influenza severity using Influenza Hospitalization Surveillance Network (FluSurv-NET) data for the 2012-2013 influenza season. Intensive care unit (ICU) admission, death, diagnosis of pneumonia, and hospital and ICU lengths of stay served as measures of disease severity. Data were analyzed by multivariable logistic regression, parametric survival models, and propensity score matching (PSM). Results.Overall, no differences in severity were observed in the multivariable logistic regression model. Using PSM, adults aged 50-64 years (but not other age groups) who were vaccinated against influenza had a shorter length of ICU stay than those who were unvaccinated (hazard ratio for discharge, 1.84; 95% confidence interval, 1.12-3.01). Conclusions.Our findings show a modest effect of influenza vaccination on disease severity. Analysis of data from seasons with different predominant strains and higher estimates of vaccine effectiveness are needed.