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Safety of Influenza Vaccination Administered During Hospitalization

Published:January 08, 2019DOI:



      To determine whether influenza vaccination during hospitalization increases health care utilization, fever, and infection evaluations postdischarge.

      Patients and Methods

      This retrospective cohort study conducted at Kaiser Permanente Southern California included patients aged 6 months or older hospitalized in a Kaiser Permanente Southern California facility with admission and discharge dates between September 1 and March 31 of the following calendar year, from 2011 to 2014. All influenza vaccinations administered during the period of August 1 to April 30 for influenza seasons 2011-2012, 2012-2013, and 2013-2014 were identified. We compared the risk of outcomes of interest between those who received influenza vaccination during their hospitalization vs those who were never vaccinated that season or were vaccinated at other times using propensity score analyses with inverse probability of treatment weighting. Outcomes of interest included rates of outpatient and emergency department visits, readmissions, fever, and clinical laboratory evaluations for infection (urine, blood, and wound culture; complete blood cell count) in the 7 days following discharge.


      We included in the study 290,149 hospitalizations among 255,737 patients. In adjusted analyses, we found no increased risk of readmissions (relative risk [RR], 0.88; 95% CI, 0.83-0.95), outpatient visits (RR, 0.97; 95% CI, 0.95-0.99), fever (RR, 0.80; 95% CI, 0.68-0.93), and clinical evaluations for infection (RR, 0.95; 95% CI, 0.92-0.98) among those vaccinated during hospitalization compared with those who were never vaccinated or were vaccinated at other times.


      Our findings provide reassurance about the safety of influenza vaccination during hospitalization. Every contact with a health care professional, including during a hospitalization, is an opportunity to vaccinate.

      Abbreviations and Acronyms:

      ED (emergency department), IPTW (inverse probability of treatment weighting), KPSC (Kaiser Permanente Southern California), Q (quartile)
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        • Centers for Disease Control and Prevention
        Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices—United States, 2013-2014.
        MMWR Recomm Rep. 2013; 62 ([published correction appears in MMWR Recomm Rep. 2013;62(45):906]): 1-43
        • VanderEnde D Spell N.
        • Graham K.
        • et al.
        A systematic approach to increasing pneumococcal and influenza vaccination rates among hospitalized patients.
        J Hosp Med. 2011; 6 ([abstract 133]): S83
        • Bloom H.G.
        • Wheeler D.A.
        • Linn J.
        A managed care organization's attempt to increase influenza and pneumococcal immunizations for older adults in an acute care setting.
        J Am Geriatr Soc. 1999; 47: 106-110
        • Short J.A.
        • van der Walt J.H.
        • Zoanetti D.C.
        Immunization and anesthesia - an international survey.
        Paediatr Anaesth. 2006; 16: 514-522
        • Mayo A.M.
        • Cobler S.
        Flu vaccines and patient decision making: what we need to know.
        J Am Acad Nurse Pract. 2004; 16: 402-410
        • Tartof S.Y.
        • Qian L.
        • Rieg G.K.
        • et al.
        Safety of seasonal influenza vaccination in hospitalized surgical patients: a cohort study.
        Ann Intern Med. 2016; 164: 593-599
        • Nichol K.L.
        Ten-year durability and success of an organized program to increase influenza and pneumococcal vaccination rates among high-risk adults.
        Am J Med. 1998; 105: 385-392
        • Lawson F.
        • Baker V.
        • Au D.
        • McElhaney J.E.
        Standing orders for influenza vaccination increased vaccination rates in inpatient settings compared with community rates.
        J Gerontol A Biol Sci Med Sci. 2000; 55: M522-M526
        • Freedman J.L.
        • Reilly A.F.
        • Powell S.C.
        • Bailey L.C.
        Quality improvement initiative to increase influenza vaccination in pediatric cancer patients.
        Pediatrics. 2015; 135: e540-e546
        • Berry B.B.
        • Ehlert D.A.
        • Battiola R.J.
        • Sedmak G.
        Influenza vaccination is safe and immunogenic when administered to hospitalized patients.
        Vaccine. 2001; 19: 3493-3498
        • Koebnick C.
        • Langer-Gould A.M.
        • Gould M.K.
        • et al.
        Sociodemographic characteristics of members of a large, integrated health care system: comparison with US Census Bureau data.
        Perm J. 2012; 16: 37-41
        • Rhee D.
        • Salazar J.H.
        • Zhang Y.
        • et al.
        A novel multispecialty surgical risk score for children.
        Pediatrics. 2013; 131: e829-e836
        • Westreich D.
        • Lessler J.
        • Funk M.J.
        Propensity score estimation: neural networks, support vector machines, decision trees (CART), and meta-classifiers as alternatives to logistic regression.
        J Clin Epidemiol. 2010; 63: 826-833
        • Austin P.C.
        An introduction to propensity score methods for reducing the effects of confounding in observational studies.
        Multivariate Behav Res. 2011; 46: 399-424
        • Yang D.
        • Dalton J.E.
        A unified approach to measuring the effect size between two groups using SAS®.
        in: SAS Global Forum, Statistics and Data Analysis. 2012 (Paper 335-2012)
        • Zou G.
        A modified Poisson regression approach to prospective studies with binary data.
        Am J Epidemiol. 2004; 159: 702-706
        • Chen W.
        • Shi J.
        • Qian L.
        • Azen S.P.
        Comparison of robustness to outliers between robust Poisson models and log-binomial models when estimating relative risks for common binary outcomes: a simulation study.
        BMC Med Res Methodol. 2014; 14: 82
        • Ver Hoef J.M.
        • Boveng P.L.
        Quasi-Poisson vs. negative binomial regression: how should we model overdispersed count data?.
        Ecology. 2007; 88: 2766-2772
        • Grijalva C.G.
        • Zhu Y.
        • Williams D.J.
        • et al.
        Association between hospitalization with community-acquired laboratory-confirmed influenza pneumonia and prior receipt of influenza vaccination.
        JAMA. 2015; 314: 1488-1497
        • Arriola C.S.
        • Anderson E.J.
        • Baumbach J.
        • et al.
        Does influenza vaccination modify influenza severity? data on older adults hospitalized with influenza during the 2012-2013 season in the United States.
        J Infect Dis. 2015; 212: 1200-1208
        • Polachek A.
        • Korobko U.
        • Mader-Balakirski N.
        • et al.
        Immunogenicity and safety of vaccination against seasonal 2012 influenza virus among patients with psoriatic arthritis and psoriasis.
        Clin Exp Rheumatol. 2015; 33: 181-186
        • Dos Santos G.
        • Haguinet F.
        • Cohet C.
        • et al.
        Risk of solid organ transplant rejection following vaccination with seasonal trivalent inactivated influenza vaccines in England: a self-controlled case-series.
        Vaccine. 2016; 34: 3598-3606
        • Liao Z.
        • Tang H.
        • Xu X.
        • Liang Y.
        • Xiong Y.
        • Ni J.
        Immunogenicity and safety of influenza vaccination in systemic lupus erythematosus patients compared with healthy controls: a meta-analysis.
        PLoS One. 2016; 11: e0147856
        • Naleway A.L.
        • Irving S.A.
        • Henninger M.L.
        • et al.
        • Vaccine Safety Datalink and Pregnancy and Influenza Project
        Safety of influenza vaccination during pregnancy: a review of subsequent maternal obstetric events and findings from two recent cohort studies.
        Vaccine. 2014; 32: 3122-3127
        • Boikos C.
        • De Serres G.
        • Lands L.C.
        • et al.
        Safety of live-attenuated influenza vaccination in cystic fibrosis.
        Pediatrics. 2014; 134 ([published correction appears in Pediatrics. 2014;134(4), doi: 10.1542/peds.2016-2521]): e983-e991
        • Halsey N.A.
        • Talaat K.R.
        • Greenbaum A.
        • et al.
        The safety of influenza vaccines in children: an Institute for Vaccine Safety white paper.
        Vaccine. 2015; 33: F1-F67
        • Loubet P.
        • Loulergue P.
        • Galtier F.
        • Launay O.
        Seasonal influenza vaccination of high-risk adults.
        Expert Rev Vaccines. 2016; 15: 1507-1518