In the previous post I provided you the clinical trial results, as reported by the manufacturer GlaxoSmithKline for their Flulaval-Tetra vaccine. I imagine you can already recognize that manufacturers typically only report on, and publish the data from clinical trials where the data was favourable for their product. Like any business, why would they publish or publicize data that wouldn’t positively promote their product?
In that previous article, the manufacturer testing showed that 100 people needed to be vaccinated, for less than 3 of those people to experience a benefit. If that's the conclusion of a manufacturers' "favourable" study, what are the results of flu studies completed by independent researchers who don't have a vested interest in the product?
To answer that, I’d like to now turn your attention to the work of the Cochrane organization. Who are they? They were a highly respected group of independent scientific researchers who were not influenced or connected to industry or government. To quote Wikipedia (emphasis mine):
Cochrane, previously known as the Cochrane Collaboration, is an independent, non-profit, non-governmental organization consisting of a group of more than 37,000 volunteers in more than 130 countries. The group was formed to organize medical research information in a systematic way to facilitate the choices that health professionals, patients, policy makers and others face in health interventions according to the principles of evidence-based medicine.
...An editorial in the Canadian Medical Association Journal in 2004 noted that Cochrane reviews appear to be more updated and of better quality than other reviews and due to their standardized methodologies, was "the best single resource for methodologic research and for developing the science of meta-epidemiology.
I say they were a highly respected group of independent scientific researchers, because recently, changes have been made that appear to be altering that structure. However, the Cochrane study that I'm going to direct your attention to here for this article discussion, was completed at a time when Cochrane was a respected and trusted organization. Cochrane has done a number of reviews on influenza vaccine clinical trials. Below, I provide several excerpts from one of their reviews titled, Vaccines for preventing influenza in healthy adults. This 2014 review states (emphasis mine):
The evidence is current to May 2013. In this update, 90 reports of 116 studies compared the effect of influenza vaccine with placebo or no intervention. Sixty-nine reports were clinical trials (over 70,000 people), 27 were comparative cohort studies (about eight million people) and 20 were case-control studies (nearly 25,000 people). Of the 116 studies, 23 (three case-control and 20 cohort studies) were performed during pregnancy (about 1.6 million mother-child couples)...
Vaccination had a modest effect on time off work and had no effect on hospital admissions or complication rates. Inactivated vaccines caused local harms. No evidence of association with serious adverse events was found, but the harms evidence base was limited...
The preventive effect of parenteral inactivated influenza vaccine on healthy adults is small: at least 40 people would need vaccination to avoid one...case [of Influenza Like Illness]... and 71 people would need vaccination to prevent one case of influenza ... Vaccination shows no appreciable effect on working days lost or hospitalization...
An earlier review of 274 influenza vaccine studies in all age groups (including most of the studies in this review) showed an inverse relationship between risk of bias and the direction of study conclusions. Conclusions favourable to the use of influenza vaccines were associated with a higher risk of bias. In these studies, the authors made claims and drew conclusions that were unsupported by the data they presented. In addition, industry-funded studies are more likely to have favourable conclusions, to be published in significantly higher-impact factor journals and to have higher citation rates than non-industry-funded studies. This difference is not explained by either their size or methodological quality. Any interpretation of the body of evidence in this review should be made with these findings in mind.
To quote the Authors Conclusion in that 2014 paper, it stated (emphasis mine):
The results of this review provide no evidence for the utilisation of vaccination against influenza in healthy adults as a routine public health measure. As healthy adults have a low risk of complications due to respiratory disease, the use of the vaccine may only be advised as an individual protective measure.
And the same review published in 2010 stated (emphasis mine):
The content and results of previous versions of this review have been extensively misquoted especially in public policy documents. Two types of common misquotes are the generalisation of evidence from this review to all age and risk groups and the generalisation of estimates of effect to all outcomes (especially complications and deaths). The misquotes then assume that the performance of influenza vaccines is uniform across all age groups and from symptom prevention to all outcomes. Both generalisations are not supported by any evidence and seem to originate from the desire to use our review to support decisions already taken. The misquotes appear to be based on both the abstract and Plain language summary (which is what you would expect from a superficial reading of the review by people with a specific agenda). It is for these reasons that in this 2010 update we have tried to minimise the risk of being misquoted by presenting effects on major outcomes…
Description of Cochrane in Wikipedia Here
Cochrane – 2014 Review (Influenza in Healthy Adults) Here
Cochrane – 2010 Review (Influenza in Healthy Adults) Here
Why it may not be wise to continue trusting Cochrane Reviews Here
CONTINUE to the next post here: Safety & Efficacy - Part 8