The sad fact though, is that there is virtually no conclusive evidence that flu vaccines are effective at preventing the flu. A recent article in the magazine, The Atlantic explains why. The belief that flu vaccines are effective comes from cohort studies. These cohort studies examine the death rates in large groups of people that choose to get vaccinated with death rates in groups that don't. The problem is that cohort studies are extremely susceptible to bias. Confounding factors like education, lifestyle and income can influence the results in a major way. In 2006 Dr. Lisa Jackson published a study in International Journal of Epidemiology to test her hypothesis that those who choose to get vaccinated tend to be younger and healthier. Her study showed that outside the flu season, people that don't get vaccinated still have a 60% higher death rate over those that do. This study clearly shows that confounding factors explain the mortality differences and not vaccine effectiveness. In other words, there is no evidence then that flu vaccines do anything but increase the profits of mega pharmaceutical companies.
The Atlantic article also notes that in 2004 there was a 40% drop in flu vaccine production rates yet mortality rates did not increase. In 1968 and 1997 the wrong flu vaccine was distributed and again there was no mortality increase. Dr. Sumit Majumdar of the University of Alberta notes that despite the dramatic increase in vaccination rates of the elderly there has been no decline in mortality rates. The Cochrane Collaboration's Tom Jefferson has extensively examined all flu vaccine studies and notes that almost all these studies were deeply flawed. Of the only four studies he found to be properly designed, only two showed any benefit and only in certain groups such as school children with no underlying health issues. As Jefferson rightly explains, the only way to conclusively determine if flu vaccines work is to perform large scale randomized placebo-controlled trial studies. Such studies involve randomly giving half the test subjects vaccine and the other half a placebo. The usual hysterical reaction to this is that it would be highly unethical to conclusively prove a treatment works because you would deny the treatment to those that need it. Unethical? Basing large scale health initiatives on highly unsound pseudo-science and circular logic is monstrously unethical. Clearly in the business of politics rational objectivity, sound science and ethics mean little.