Check out this study done by a Havard post doctoral fellow on the Flu Shot! So how could these studies—both published in high impact, peer reviewed journals and carried out by academic and government researchers with non-commercial funding—get it wrong? Consider one study the CDC does not cite, which found influenza vaccination associated with a 51% reduced odds of death in patients hospitalized with pneumonia (28 of 352 [8%] vaccinated subjects died versus 53 deaths among 352 [15%] unvaccinated control subjects).16 Although the results are similar to those of the studies CDC does cite, an unusual aspect of this study was that it focused on patients outside of the influenza season—when it is hard to imagine the vaccine could bring any benefit. And the authors, academics from Alberta, Canada, knew this: the purpose of the study was to demonstrate that the fantastic benefit they expected to and did find—and that others have found, such as the two studies that CDC cites—is simply implausible, and likely the product of the “healthy-user effect” (in this case, a propensity for healthier people to be more likely to get vaccinated than less healthy people).Others have gone on to demonstrate this bias to be present in other influenza vaccine studies.17 18 Healthy user bias threatens to render the observational studies, on which officials’ scientific case rests, not credible. Yet for most people, and possibly most doctors, officials need only claim that vaccines save lives, and it is assumed there must be solid research behind it. But for those that bother to read the CDC’s national guidelines19—a 68 page document of 33360 words and 552 references—one finds that the evidence cited is these observational studies that the agency itself acknowledges may be undermined by bias. The guidelines state: “...studies demonstrating large reductions in hospitalizations and deaths among the vaccinated elderly have been conducted using medical record databases and have not measured reductions in laboratory-confirmed influenza illness. These studies have been challenged because of concerns that they have not controlled adequately for differences in the propensity for healthier persons to be more likely than less healthy persons to receive vaccination.”19 CDC does not rebut or in any other way respond to these criticisms. It simply acknowledges them, and leaves it at that. If the observational studies cannot be trusted, what evidence is there that influenza vaccines reduce deaths of older people—the reason the policy was originally created? Virtually none. All influenza is “flu, ” but only one in six “ flus ” might be influenza. It’s no wonder so many people feel that “flu shots” don’t work: for most flus, they can’t. [email protected] ncbi.nlm.nih.gov/pubmed/23682040 Click on the BMJ Full text link on the right to view the study
Posted on: Fri, 10 Oct 2014 10:10:26 +0000
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