Influenza- and respiratory syncytial virus-associated adult mortality in Soweto.
BACKGROUND
Influenza and respiratory syncytial virus (RSV) infections cause seasonal excess mortality and hospitalisation in adults (particularly the elderly) in high-income countries. Little information exists on the impact of these infections on adults in Africa.


OBJECTIVE
To estimate influenza- and RSV-related adult mortality, stratified by age and hospitalisation in Soweto.


METHODS
A retrospective hospital-based study in Soweto from 1997 to 1999 to estimate influenza- and RSV-related excess all-cause deaths and hospitalisation using a rate-difference method. The study was based on influenza seasons of varying severity, provided by surveillance data.


RESULTS
Influenza seasons were significantly associated with excess mortality in adults across all 3 years, except for 18 - 64-year-olds in 1998. Excess mortality was highest in those > or = 65 years of age: 82.8/100 000 population in the mild 1997 season and 220.9/100 000 in the severe 1998 season. Influenza significantly increased adult medical hospitalisation in the severe 1998 season alone. RSV did not significantly affect mortality or hospitalisation.


CONCLUSIONS
Influenza-related mortality was substantial and disproportionately affected the elderly. Influenza vaccination for the elderly warrants consideration. The RSV-related burden was not significantly increased but merits observation over a longer period.
Karstaedt
A S
AS
Department of Medicine, Chris Hani Baragwanath Hospital and University of the Witwatersrand, Johannesburg. karstaedt@mweb.co.za
Hopley
M
M
Wong
M
M
Crewe-Brown
H H
HH
Tasset-Tisseau
A
A
D000328:Adult; D000368:Aged; D015897:Comorbidity; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007251:Influenza, Human / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D018357:Respiratory Syncytial Virus Infections / Q000401:mortality*; D013019:South Africa / Q000453:epidemiology