Other respiratory viruses are important contributors to adult respiratory hospitalizations and mortality even during peak weeks of the influenza season.
BACKGROUND
During peak weeks of seasonal influenza epidemics, severe respiratory infections without laboratory confirmation are typically attributed to influenza.


METHODS
In this prospective study, specimens and demographic and clinical data were collected from adults admitted with respiratory symptoms to 4 hospitals during the 8-10 peak weeks of 2 influenza seasons. Specimens were systematically tested for influenza and 13 other respiratory viruses (ORVs) by using the Luminex RVP FAST assay.


RESULTS
At least 1 respiratory virus was identified in 46% (21% influenza, 25% noninfluenza; 2% coinfection) of the 286 enrolled patients in 2011-2012 and in 62% (46% influenza, 16% noninfluenza; 3% coinfection) of the 396 enrolled patients in 2012-2013. Among patients aged ≥75 years, twice as many ORVs (32%) as influenza viruses (14%) were detected in 2011-2012. During both seasons, the most frequently detected ORVs were enteroviruses/rhinoviruses (7%), respiratory syncytial virus (6%), human metapneumovirus (5%), coronaviruses (4%), and parainfluenza viruses (2%). Disease severity was similar for influenza and ORVs during both seasons.


CONCLUSIONS
Although ORV contribution relative to influenza varies by age and season, during the peak weeks of certain influenza seasons, ORVs may be a more frequent cause of elderly hospitalization than influenza.
Biological, Environmental and Occupational Risks , Institut national de santé publique du Québec ; Public Health Research Unit , Centre Hospitalier Universitaire de Québec ; Faculty of Medicine , Laval University , Québec City.
Rodica
R
Gilca
Biological, Environmental and Occupational Risks , Institut national de santé publique du Québec.
Rachid
R
Amini
Biological, Environmental and Occupational Risks , Institut national de santé publique du Québec.
Monique
M
Douville-Fradet
Laboratoire de Santé Publique du Québec , Institut national de santé publique du Québec.
Hugues
H
Charest
Ministère de la Santé et des Services sociaux, Montreal, Québec.
Josée
J
Dubuque
Biological, Environmental and Occupational Risks , Institut national de santé publique du Québec ; Public Health Research Unit , Centre Hospitalier Universitaire de Québec.
Nicole
N
Boulianne
Influenza and Emerging Respiratory Pathogens , British Columbia Centre for Disease Control , Vancouver , Canada.
Danuta M
DM
Skowronski
Biological, Environmental and Occupational Risks , Institut national de santé publique du Québec ; Public Health Research Unit , Centre Hospitalier Universitaire de Québec ; Faculty of Medicine , Laval University , Québec City.
Gaston
G
De Serres
adults; elderly; hospitalization; influenza; mortality; respiratory viruses