Effects of annual influenza vaccination on winter mortality in elderly people with chronic heart disease.
OBJECTIVE
Although there is general agreement for the recommendation of the influenza vaccine to elderly and high-risk adults, the magnitude of clinical effectiveness and benefit from the annual vaccination is controversial. In this study, we have assessed the effects of annual influenza vaccination on winter mortality in older adults with chronic heart disease.


RESULTS
Cohort study that included 1340 Spanish community-dwelling individuals 65 years or older who had chronic heart disease (congestive heart failure or coronary artery disease) followed from January 2002 to April 2005. Annual influenza vaccine status was a time-varying condition and primary outcome was all-cause death during the study period. Multivariable Cox proportional-hazard models adjusted by age, sex, and comorbidity were used to evaluate vaccine effectiveness. Influenza vaccination was associated with a significant reduction of 37% in the adjusted risk of winter mortality during the overall period 2002-2005. The attributable mortality risk reduction in vaccinated people was 8.2 deaths per 1000 person-winters. We estimated that one death was prevented for every 122 annual vaccinations (ranging between 49 in Winter 2005 and 455 in Winter 2003).


CONCLUSIONS
Our results suggest a benefit from the influenza vaccination and support an annual vaccination strategy for elderly people with cardiac diseases.
de Diego
Cinta
C
Primary Care Service of Tarragona-Valls, Institut Català de la Salut, Prat de la Riba 39, Tarragona 43001, Catalonia, Spain. cintaddc@tinet.org
Vila-Córcoles
Angel
A
Ochoa
Olga
O
Rodriguez-Blanco
Teresa
T
Salsench
Elisabeth
E
Hospital
Imma
I
Bejarano
Ferran
F
Del Puy Muniain
M
M
Fortin
Mercé
M
Canals
Montserrat
M
D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D004812:Epidemiologic Methods; D005260:Female; D006331:Heart Diseases / Q000150:complications / Q000401:mortality*; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000150:complications / Q000401:mortality* / Q000517:prevention & control; D008297:Male; D012621:Seasons; D014611:Vaccination / Q000401:mortality*
D007252:Influenza Vaccines