tetano
Editor, Senior Moderator
Clin Infect Dis. (2013) doi: 10.1093/cid/cit404 First published online: June 20, 2013
Vaccine effectiveness against laboratory-confirmed influenza hospitalizations among elderly adults during the 2010-2011 season
Jeffrey C. Kwong1,2,3,4,5,
Michael A. Campitelli1,
Jonathan B. Gubbay4,6,7,8,
Adriana Peci4,
Anne-Luise Winter4,
Romy Olsha4,
Robert Turner1,
Laura C. Rosella3,4, and
Natasha S. Crowcroft3,4,6
+ Author Affiliations
1Institute for Clinical Evaluative Sciences, Toronto, Canada
2Department of Family and Community Medicine, University of Toronto, Toronto, Canada
3Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
4Ontario Agency for Health Protection and Promotion, Toronto, Canada
5University Health Network, Toronto, Canada
6Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
7Mount Sinai Hospital, Toronto, Canada
8The Hospital for Sick Children, Toronto, Canada
corresponding author: Dr. Jeff Kwong, Institute for Clinical Evaluative Sciences, 2075 Bayview Ave, Room G1-06, Toronto, Ontario, M4N 3M5, CANADA, Email: jeff.kwong@utoronto.ca, Tel: 416-480-4055 x1-7665, Fax: 416-480-6048
alternate corresponding author: Michael Campitelli, Institute for Clinical Evaluative Sciences, 2075 Bayview Ave, Room G1-06, Toronto, Ontario M4N 3M5, CANADA, Email: michael.campitelli@ices.on.ca, Tel: 416-480-4055 x1-89337, Fax: 416-480-6048
Abstract
Background. Although annual influenza immunization is recommended for adults aged ≥65 years due to the substantial burden of illness, the evidence base for this recommendation is weak. Prior observational studies that examined influenza vaccine effectiveness against non-specific serious outcomes suffered from selection bias and the lack of laboratory confirmation for influenza infection. The objective of this study was to determine the effectiveness of the 2010-2011 seasonal influenza vaccine against laboratory-confirmed influenza hospitalizations among community-dwelling elderly adults, a serious and highly specific outcome.
Methods. We conducted a test-negative study of community-dwelling adults aged >65 years in Ontario, Canada. Respiratory specimens collected between December 1, 2010 and April 30, 2011 from patients admitted to acute care hospitals were tested for influenza using nucleic acid amplification techniques. Influenza vaccination was ascertained from physician billing claims through linkage to health administrative datasets.
Results. Receipt of the 2010-11 seasonal influenza vaccine was associated with a 42% (95% CI, 29-53%) reduction in laboratory-confirmed influenza hospitalizations. Vaccine effectiveness estimates were consistent across age groups, by sex, and regardless of outcome severity, timing of testing, and removal of individuals vaccinated <7 or <14 days prior to admission.
Conclusions. Results of this study will better inform decision-making regarding influenza vaccination of elderly adults. Similar analyses are needed annually due to antigenic drift and frequent changes in influenza vaccine composition. The linkage of routinely collected laboratory testing and health administrative data represents an efficient method for estimating influenza vaccine effectiveness that complements prospective studies.
http://cid.oxfordjournals.org/content/early/2013/06/20/cid.cit404.abstract
Vaccine effectiveness against laboratory-confirmed influenza hospitalizations among elderly adults during the 2010-2011 season
Jeffrey C. Kwong1,2,3,4,5,
Michael A. Campitelli1,
Jonathan B. Gubbay4,6,7,8,
Adriana Peci4,
Anne-Luise Winter4,
Romy Olsha4,
Robert Turner1,
Laura C. Rosella3,4, and
Natasha S. Crowcroft3,4,6
+ Author Affiliations
1Institute for Clinical Evaluative Sciences, Toronto, Canada
2Department of Family and Community Medicine, University of Toronto, Toronto, Canada
3Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
4Ontario Agency for Health Protection and Promotion, Toronto, Canada
5University Health Network, Toronto, Canada
6Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
7Mount Sinai Hospital, Toronto, Canada
8The Hospital for Sick Children, Toronto, Canada
corresponding author: Dr. Jeff Kwong, Institute for Clinical Evaluative Sciences, 2075 Bayview Ave, Room G1-06, Toronto, Ontario, M4N 3M5, CANADA, Email: jeff.kwong@utoronto.ca, Tel: 416-480-4055 x1-7665, Fax: 416-480-6048
alternate corresponding author: Michael Campitelli, Institute for Clinical Evaluative Sciences, 2075 Bayview Ave, Room G1-06, Toronto, Ontario M4N 3M5, CANADA, Email: michael.campitelli@ices.on.ca, Tel: 416-480-4055 x1-89337, Fax: 416-480-6048
Abstract
Background. Although annual influenza immunization is recommended for adults aged ≥65 years due to the substantial burden of illness, the evidence base for this recommendation is weak. Prior observational studies that examined influenza vaccine effectiveness against non-specific serious outcomes suffered from selection bias and the lack of laboratory confirmation for influenza infection. The objective of this study was to determine the effectiveness of the 2010-2011 seasonal influenza vaccine against laboratory-confirmed influenza hospitalizations among community-dwelling elderly adults, a serious and highly specific outcome.
Methods. We conducted a test-negative study of community-dwelling adults aged >65 years in Ontario, Canada. Respiratory specimens collected between December 1, 2010 and April 30, 2011 from patients admitted to acute care hospitals were tested for influenza using nucleic acid amplification techniques. Influenza vaccination was ascertained from physician billing claims through linkage to health administrative datasets.
Results. Receipt of the 2010-11 seasonal influenza vaccine was associated with a 42% (95% CI, 29-53%) reduction in laboratory-confirmed influenza hospitalizations. Vaccine effectiveness estimates were consistent across age groups, by sex, and regardless of outcome severity, timing of testing, and removal of individuals vaccinated <7 or <14 days prior to admission.
Conclusions. Results of this study will better inform decision-making regarding influenza vaccination of elderly adults. Similar analyses are needed annually due to antigenic drift and frequent changes in influenza vaccine composition. The linkage of routinely collected laboratory testing and health administrative data represents an efficient method for estimating influenza vaccine effectiveness that complements prospective studies.
http://cid.oxfordjournals.org/content/early/2013/06/20/cid.cit404.abstract