O n Nov. 6, the most comprehensive analysis of flu shot efficacy and efficiency was published in the British medical journal, The Lancet.
The authors concluded that the flu vaccine provided only moderate protection against influenza and in some years it made very little difference at all.
Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, stated that until now “no published meta-analysis has assessed the efficacy and effectiveness of licensed influenza vaccines in the USA with sensitivity and highly specific diagnostic test to confirm influenza.”
His study is, to date, the largest and most conclusive study on the matter. His research analyzed 5,707 articles published between 1967 and 2001.
In analyzing these thousands of studies for statistical significance and proper design, he found that only 31 studies effectively and appropriately measured the relationship between influenza vaccination and influenza.
He concluded that the great majority of studies, those that were disqualified from the study, vastly overestimated the health benefits of receiving influenza vaccine.
His meta-analysisfound that the vaccine was about 59% effective overall in individuals 18 to 65 years of age. In other words, more than 40% of individuals who receive the flu shot received no protection against the flu.
He further stated that an influenza vaccine ideally should be 85 to 95% effective for all ages to be considered a good vaccine.
Dr. Joseph Bresee, chief of the epidemiological and prevention branch and the National Centers for Disease Control’s Influenza Division, felt like a 59% estimate is appropriate.
Interesting enough, the CDC has downgraded the estimated effectiveness of influenza vaccine from 70 to 90% to 50 to 70%.
When analyzing study design and deeming whether or not it was appropriate or flawed, he found that “no such trials met inclusion criteria for children aged 2 to 17 years or adults 65 years or older.”
So in essence, Dr. Bresee is saying that there are no studies to date that have effectively looked at the effectiveness of the flu vaccine from the ages of 2 to 17 and 65 or older.
In his published, peer-reviewed study he states: “Every year, large-scale campaigns in many developed countries are undertaken to vaccinate all people aged 65 years or older to prevent serious illness and mortality.
“With an estimated 90% of all seasonal influenza related mortality occurring in this group, and effective intervention is an important public health priority. However, this is the age group for which we have the least data supporting the efficacy or effectiveness of influenza vaccines to reduce morbidity and mortality.
This article contains no less than 71 references and can be viewed online at The Lancet.