Mortality attributable to 9 common infections: significant effect of influenza A, respiratory syncytial virus, influenza B, norovirus, and parainfluenza in elderly persons.
BACKGROUND
Because there may be substantial hidden mortality caused by common seasonal pathogens, we estimated the number of deaths in elderly persons attributable to viruses and bacteria for which robust weekly laboratory surveillance data were available.


METHODS
On weekly time series (1999-2007) we used regression models to associate total death counts in individuals aged 65-74, 75-84, and ≥85 years (a population of 2.5 million) with pathogen circulation-influenza A (season-specific), influenza B, respiratory syncytial virus (RSV), parainfluenza, enterovirus, rotavirus, norovirus, Campylobacter, and Salmonella-adjusted for extreme outdoor temperatures.


RESULTS
Influenza A and RSV were significantly (P < .05) associated with mortality in all studied age groups; influenza B and parainfluenza were additionally associated in those aged ≥75 years, and norovirus was additionally associated in those aged ≥85 years. The proportions of deaths attributable to seasonal viruses were 6.8% (≥85 years), 4.4% (75-84 years), and 1.4% (65-74 years), but with great variations between years. Influenza occasionally showed lower impact than some of the other viruses.


CONCLUSIONS
The number of different pathogens associated with mortality in the older population increases with increasing age. Besides influenza A and RSV, influenza B, parainfluenza and norovirus may also contribute substantially to elderly mortality.
Centre for Infectious Disease Control Netherlands, National Institute for Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands. liselotte.van.Asten@rivm.nl
Liselotte
L
van Asten
Cees
C
van den Wijngaard
Wilfrid
W
van Pelt
Jan
J
van de Kassteele
Adam
A
Meijer
Wim
W
van der Hoek
Mirjam
M
Kretzschmar
Marion
M
Koopmans
D000368:Aged; D000369:Aged, 80 and over; D017250:Caliciviridae Infections / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D002169:Campylobacter Infections / Q000453:epidemiology / Q000382:microbiology / Q000401:mortality*; D004769:Enterovirus Infections / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D009426:Netherlands / Q000453:epidemiology; D018184:Paramyxoviridae Infections / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D012044:Regression Analysis; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000401:mortality* / Q000821:virology; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology / Q000401:mortality*; D012621:Seasons