tetano
Editor, Senior Moderator
Clin Infect Dis. 2020 Jan 6. pii: ciz1238. doi: 10.1093/cid/ciz1238. [Epub ahead of print] [h=1]Influenza vaccine effectiveness against influenza-related mortality in Australian hospitalized patients: a propensity score analysis.[/h]
Nation ML[SUP]1,[/SUP][SUP]2[/SUP], Moss R[SUP]2[/SUP], Spittal MJ[SUP]2[/SUP], Kotsimbos T[SUP]3[/SUP], Kelly PM[SUP]4[/SUP], Cheng AC[SUP]5[/SUP].
[h=3]Author information[/h] 1 Infection and Immunity, Murdoch Children's Research Institute, Melbourne, Australia. 2 Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia. 3 Department of Allergy, Immunology and Respiratory Medicine, Alfred Health, Monash University, Melbourne, Australia. 4 Australian National University Medical School, Canberra, Australia. 5 Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
[h=3]Abstract[/h] [h=4]BACKGROUND:[/h] Data on influenza vaccine effectiveness (IVE) against mortality is limited, with no Australian data to guide vaccine uptake. We aimed to assess IVE against influenza-related mortality in Australian hospitalized patients; assess residual confounding in the association between influenza vaccination and mortality; and assess whether influenza vaccination reduces the severity of influenza illness.
[h=4]METHODS:[/h] Data were collected between 2010-2017 from a national Australian hospital-based sentinel surveillance system using a case-control design. Adults and children admitted to the 17 study hospitals with acute respiratory symptoms were tested for influenza using nucleic acid testing; all eligible test-positive cases were included, and a subset of test-negative controls. Propensity score analysis and multivariable logistic regression were used to determine the adjusted Odds Ratio (aOR) of vaccination, with IVE= 1-aOR x 100%. Residual confounding was assessed by examining mortality in controls.
[h=4]RESULTS:[/h] Over eight seasons, 14038 patients were admitted with laboratory-confirmed influenza. The primary analysis included 9298 cases and 6451 controls, with 194 cases and 136 controls dying during hospitalization. Vaccination was associated with a 31% (95%CI: 3-51%, p=0.033) reduction in influenza-related mortality, with similar estimates in the National Immunisation Program target group. Residual confounding was identified in patients ≥65 years old (aOR: 1.92 (95%CI: 1.06-3.46); p=0.031). There was no evidence that vaccination reduced the severity of influenza illness (aOR: 1.07 (95%CI: 0.76-1.50); p=0.713).
[h=4]CONCLUSIONS:[/h] Influenza vaccination is associated with a moderate reduction in influenza-related mortality. This finding reinforces the utility of the Australian vaccination program in protecting those most at risk of influenza-related deaths.
? The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
[h=4]KEYWORDS:[/h] Influenza vaccination; case-control; mortality; propensity score analysis; vaccine effectiveness
PMID: 31903487 DOI: 10.1093/cid/ciz1238
Nation ML[SUP]1,[/SUP][SUP]2[/SUP], Moss R[SUP]2[/SUP], Spittal MJ[SUP]2[/SUP], Kotsimbos T[SUP]3[/SUP], Kelly PM[SUP]4[/SUP], Cheng AC[SUP]5[/SUP].
[h=3]Author information[/h] 1 Infection and Immunity, Murdoch Children's Research Institute, Melbourne, Australia. 2 Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia. 3 Department of Allergy, Immunology and Respiratory Medicine, Alfred Health, Monash University, Melbourne, Australia. 4 Australian National University Medical School, Canberra, Australia. 5 Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
[h=3]Abstract[/h] [h=4]BACKGROUND:[/h] Data on influenza vaccine effectiveness (IVE) against mortality is limited, with no Australian data to guide vaccine uptake. We aimed to assess IVE against influenza-related mortality in Australian hospitalized patients; assess residual confounding in the association between influenza vaccination and mortality; and assess whether influenza vaccination reduces the severity of influenza illness.
[h=4]METHODS:[/h] Data were collected between 2010-2017 from a national Australian hospital-based sentinel surveillance system using a case-control design. Adults and children admitted to the 17 study hospitals with acute respiratory symptoms were tested for influenza using nucleic acid testing; all eligible test-positive cases were included, and a subset of test-negative controls. Propensity score analysis and multivariable logistic regression were used to determine the adjusted Odds Ratio (aOR) of vaccination, with IVE= 1-aOR x 100%. Residual confounding was assessed by examining mortality in controls.
[h=4]RESULTS:[/h] Over eight seasons, 14038 patients were admitted with laboratory-confirmed influenza. The primary analysis included 9298 cases and 6451 controls, with 194 cases and 136 controls dying during hospitalization. Vaccination was associated with a 31% (95%CI: 3-51%, p=0.033) reduction in influenza-related mortality, with similar estimates in the National Immunisation Program target group. Residual confounding was identified in patients ≥65 years old (aOR: 1.92 (95%CI: 1.06-3.46); p=0.031). There was no evidence that vaccination reduced the severity of influenza illness (aOR: 1.07 (95%CI: 0.76-1.50); p=0.713).
[h=4]CONCLUSIONS:[/h] Influenza vaccination is associated with a moderate reduction in influenza-related mortality. This finding reinforces the utility of the Australian vaccination program in protecting those most at risk of influenza-related deaths.
? The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
[h=4]KEYWORDS:[/h] Influenza vaccination; case-control; mortality; propensity score analysis; vaccine effectiveness
PMID: 31903487 DOI: 10.1093/cid/ciz1238