Prevention of influenza in the general population: recommendation statement from the Canadian Task Force on Preventive Health Care

I find it interesting, a few weeks after a celebration of the achievements of the Cochrane Collaboration in these pages (largely in honouring Cochrane's vision of synthesized evidence, I have yet to see the zeal for the provision of all effective health care free in the Cochrane Collaboration, a tenet equally dear to the heart of their patroin saint) that CMAJ publishes a systematic review of influenza vaccine and Period Task Force Report and the systematic review authors are quoted in the Toronto Globe and Mail as endorsing universal vaccination, when a Cochrane review on the topic already exists. ("Ideally, we would like to have everyone immunized against influenza," said task force member Joanne Langley of the Department of Community Health and Epidemiology at Dalhousie University."Universal vaccination would likely be of great benefit and unlikely to cause any significant harm, so we are recommending this approach," she said in an interview.)The newly appointed Chief Medical Officer of Health for Canada argues that universal vaccination is not the best use of scarce resources.

The Cochrane Systematic Review , alluded to but not quoted by the authors of the systematic review concludes: "Influenza vaccines are effective in reducing serologically confirmed cases of influenza. However, they are not as effective in reducing cases of clinical influenza and number of working days lost. Universal immunisation of healthy adults is not supported by the results of this review."

Langly and Faughnan write in their review "The goal of our review was to determine the efficacy of the influenza vaccine and neuraminidase inhibitors, not to determine the efficacy of a universal immunization program. With such a program, considerations that must be weighed against the potential benefits (preventing illness and death in high-risk groups, and decreasing economic loss associated with absenteeism at work, visits to health care providers and antibiotic use) include the economic costs of vaccine and program delivery, vaccine procurement for large populations, the need to immunize large populations in a short period each year and public acceptability. "

Yet the task force and authors endorse such a strategy, without evidence provided on these ancilliary considerations.

Something is missing here. Is the CMAJ systematic review not the compelling piece of evidence leading to the endoresement? Is the Cochrane Collaboration wrong in its conclusion? Is there evidence of cost effectiveness and are procurement issues sorted out? Is Dr Butler Jones correct about the priority of chronic disease prevention over influenza prevention? Just how many systematic reviews on a topic do we need anyway?

Interestingly RA Fisher envisioned controlled trials (and by extension systematic reviews and meta-analysis) as techniques to reduce interpretive variability of study results. I wish he and Archie Cochrane were still around to help me sort this out!

Best Regards

Ross Upshur

Conflict of Interest:

None declared