Risk Of Death Not Reduced By Flu Shot

�The widely-held perception that the influenza vaccination reduces overall mortality risk in the aged does non withstand careful scrutiny, according to researchers in Alberta. The vaccine does confer protection against specific strains of flu, but its overall benefit appears to have been exaggerated by a figure of experimental studies that found a very large reduction in all-cause mortality among aged patients world Health Organization had been vaccinated.



The results will appear in the first issuing for September of the American Journal of Respiratory and Critical Care Medicine, a publication of the American Thoracic Society.



The study included more than 700 matched elderly subjects, half of whom had interpreted the vaccine and half of whom had not. After controlling for a wealth of variables that were largely not considered or simply not available in previous studies that reported the mortality benefit, the researchers concluded that any such benefit "if present at all, was very little and statistically non-significant and may just be a healthy-user artifact that they were unable to identify."



"While such a reduction in all-cause mortality rate would have been impressive, these mortality rate benefits ar likely implausible. Previous studies were likely measuring a benefit non directly attributable to the vaccine itself, but something specific to the individuals who were vaccinated - a healthy-user benefit or frailty bias," said Dean T. Eurich,Ph.D. clinical epidemiologist and supporter professor at the School of Public Health at the University of Alberta. "Over the last two decades in the United Sates, even while inoculation rates among the aged have increased from 15 to 65 percent, on that point has been no commensurate decrease in hospital admissions or all-cause mortality. Further, only almost 10 percent of wintertime deaths in the United States ar attributable to influenza, so to suggest that the vaccine can reduce 50 percent of deaths from all causes is implausible in our opinion."



Dr. Eurich and colleagues hypothesized that if the healthy-user effect was responsible for for the mortality benefit associated with influenza vaccination seen in observational studies, there should also be a significant mortality benefit present during the "off-season".



To determine whether the discovered mortality benefits were actually an effect of the flu vaccinum, therefore, they analyzed clinical data from records of all six hospitals in the Capital Health region in Alberta. In summate, they analyzed data from 704 patients 65 years of years and old who were admitted to the infirmary for community-acquired pneumonia during non-flu season, half of whom had been immunised, and