Influenza vaccine protective in elderly patients
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Trivalent influenza vaccine was protective against influenza-related hospitalization among older adults who were not frail, despite common conceptions that vaccine effectiveness is low in older patients, study data showed.
Researchers reported, however, that vaccine effectiveness decreased as patients’ frailty increased.
“While there is evidence that influenza vaccination is effective in reducing medically attended influenza, hospitalization and mortality, vaccine effectiveness in elderly patients appears modest; estimates of [vaccine effectiveness] against laboratory-confirmed influenza hospitalization rage from 33% to 86%,” Melissa K. Andrew, MD, PhD, of the Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, and colleagues wrote. “This variability has led to controversy about the value of influenza vaccines in protecting elderly people against hospitalization and serious outcomes.”
Andrew and colleagues performed a multicenter, prospective, test-negative case-control study on 320 patients with influenza virus infection and 564 controls during the 2011 to 2012 influenza season. The patients’ mean age was 80.6 years for cases and 78.7 years for controls. At baseline, cases were more frail than controls (P = .006). A fully adjusted model showed that vaccine effectiveness was 58%, (95% CI, 34.2-73.2%), the researchers reported. Adjusting for frailty alone produced an effectiveness of 58.7% (95% CI, 36.2%-73.2%). Among patients who were not considered frail, vaccine effectiveness was 77.6%, and decreased as frailty increased.
“As demonstrated by Andrew et al, persons aged 65 years are a heterogeneous group in regard to frailty,” Kathleen M. Neuzil, MD, MPH, an Infectious Disease News Editorial Board member and professor at the University of Maryland School of Medicine, and Wilbur H. Chen, MD, associate professor at the University of Maryland School of Medicine, wrote in an accompanying editorial. “All should receive influenza vaccine. For some older persons, the primary motivations for receiving influenza vaccine will be to avoid both serious complications of influenza as well as serious illness that interferes with their ability to work, travel and enjoy a physically active lifestyle. These data, along with data from head-to-head vaccine comparisons, will best guide influenza vaccine policy going forward.” – by Andy Polhamus
Disclosure: Neuzil reports no relevant financial disclosures. Chen reports advisory roles with GlaxoSmithKline and Novavax. Andrew reports grants from GSK, Pfizer and Sanofi Pasteur.