No Value in Any Influenza Vaccine: Cochrane Collaboration Study

A remarkable study published in the Cochrane Library found no evidence of benefit for influenza vaccinations. It’s also damns the quality of flu vaccine studies by saying that the vast majority of trials were inadequate. The authors stated that the only ones showing benefit were industry-funded. They also pointed out that the industry-funded studies were more likely to be published in the most prestigious journals … and one more thing: They found cases of severe harm caused by the vaccines, in spite of inadequate reporting of adverse effects.

The study, Vaccines for preventing influenza in healthy adults, is damning of the entire pharmaceutical industry and its minions: the drug testing industry and the medical system that both relies on and promotes them.

In the usual scientific journal style of understatement, the authors concluded:

The results of this review seem to discourage 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 be only advised as an individual protection measure against symptoms in specific cases.
The Study

The authors attempted to find and investigate every study that has evaluated the effects of flu vaccines in healthy adults aged 18-65. To this end, they “searched Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2010, issue 2), MEDLINE (January 1966 to June 2010) and EMBASE (1990 to June 2010).” They included 50 reports. Forty of them were clinical trials adding up to over 70,000 people. Two reported only on harmful effects and were not included in this study. Studies of all types of influenza vaccines were included: live, attenuated, and killed—or fractions of killed—vaccines.

The primary outcomes they looked for were numbers and seriousness of influenza and influenza-like illnesses. They also looked at the number and seriousness of harms from the vaccines. The authors attempted to collect missing data by writing to the individual studies’ authors. They describe the response as “disappointing”. In the end, they included 50 studies and refused to use 92, mostly because of highly significant flaws, such as using inappropriate controls, not being randomly controlled trials, inconsistencies in data presented, lack of study design, unclear definitions, poor reporting, lack of crude data, and lack of placebo.

The authors found:
Vaccines administered parenterally, that is, outside the digestive tract—which generally means by injection—reduced influenza-like symptoms by only 4%.
They found no evidence that vaccination prevents viral transmission in healthy adults! (There goes the whole herd immunity argument!) This is particularly significant because, as they noted, inactivated vaccines are known to perform best in healthy adults.
They also found no evidence that flu vaccines prevent complications, either. They attempted to ascertain the degree of complications, and though they did report on some, most of the studies simply did not address the issue or did so inadequately.
Conclusions

The Cochrane study found very little evidence to support even a small improvement in time off work. Even that finding needs to be put into the context of industry influence. The authors wrote:

This review includes 15 out of 36 trials funded by industry (four had no funding declaration). An earlier systematic review of 274 influenza vaccine studies published up to 2007 found industry funded studies were published in more prestigious journals and cited more than other studies independently from methodological quality and size. Studies funded from public sources were significantly less likely to report conclusions favorable to the vaccines. The review showed that reliable evidence on influenza vaccines is thin but there is evidence of widespread manipulation of conclusions and spurious notoriety of the studies. The content and conclusions of this review should be interpreted in light of this finding.

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