'Did you have flu last week?' A telephone survey to estimate a point prevalence of influenza in the Swedish population.
Sentinel surveillance usually underestimates the true burden of influenza in a population, as individuals must present to medical establishments to be included in the surveillance system. We carried out a telephone survey to estimate the national burden of influenza in the Swedish population for one week during the 2004/05 influenza season. Fixed-line telephone numbers were randomly sampled and households interviewed concerning influenza illness between 14-20 February 2005 (Week 7 of 2005). Questions regarding seasonal influenza vaccination status, symptoms and the impact of illness on daily life were also included. A self-defined influenza prevalence of 7.7% in week 7 of 2005 was estimated. On applying a case definition of 'cough and fever and muscle pain' for influenza like illness, the prevalence decreased to 3.6%. The survey provided insight into the burden of illness in the population further to that estimated through the sentinel surveillance system.
Payne
L
L
Dept. of Epidemiology, Swedish Institute for Infectious Disease Control, Sweden.
Kühlmann-Berenzon
S
S
Ekdahl
Karl
K
Giesecke
J
J
Högberg
L
L
Penttinen
P
P
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003371:Cough / Q000209:etiology; D003430:Cross-Sectional Studies; D003625:Data Collection; D005334:Fever / Q000209:etiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology / Q000517:prevention & control; D008875:Middle Aged; D009132:Muscles; D010146:Pain / Q000209:etiology; D015995:Prevalence; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013548:Sweden / Q000453:epidemiology; D014611:Vaccination