Globe and Mail Thursday, Aug. 06, 2009 03:12AM EDT

Alan Cassels and Arthur Schafer
What do we know about the vaccines' safety? Not enough
In the headlong rush to do good, we need to be sure we don't end up doing harm

Who should be at the top of the list to receive the H1N1 vaccine or antiviral drugs if, as feared, they are in short supply? Bio-ethicists debate the niceties of how society should ration scarce medical resources, while public-health officials spend their days debating who should be first in line – pregnant women, health-care personnel or perhaps government leaders and corporate CEOs?

The majority of Canadians, listening to this rationing debate, would be forgiven for assuming that the H1N1 vaccine, when it becomes available in the autumn, will be a life saver. The unfortunate reality, however, is that we don't know and, indeed, can't know if that is the case.

Like most governments around the world, eager to appear to be “doing something,” the government of Canada has promised to stockpile enough of the vaccine so that most Canadians will be protected.

But, speaking of stockpiles, Canada already owns one of the world's largest supplies of antiviral drugs, mostly Tamiflu and Relenza, two drugs designed to reduce the severity and length of the flu. And yet the scientific evidence testing the preventive benefits of either Tamiflu or its near cousin, Relenza, shows that both are pathetically weak. People who take either of these “prophylactically,” i.e. before they become sick, hoping to prevent the flu, will get about as much effect as if they'd taken a placebo. That's not a very impressive result. Equally unimpressive: When the drugs are given within 48 hours to someone who already has flu symptoms, with the goal of ameliorating the severity of the disease, it makes only a slight difference. The “lucky ones” who take Tamiflu may reduce the average length of a five-day flu by about half a day. Not worth getting out of bed for, you might think. So perhaps it doesn't matter all that much who is at the top of the list to receive the drugs and who is at the bottom.

Consider also that a recent international study reveals that about 50 per cent of children who have taken Tamiflu experienced side effects. Most have been minor (gut problems, diarrhea) but some have been more serious, including neuropsychiatric problems. Why are public-health officials glossing over the fact there is a great deal of uncertainty and doubt surrounding the effectiveness, safety and side effects of flu drugs?

The same could be said for the H1N1 vaccine, currently in production and ramped up for Canada's fall flu season. What do we know about its effectiveness or its safety? The answer is, not enough. If one takes past flu campaigns as any indication, it is likely the effectiveness of the vaccine is going to be exaggerated, while the potential harms will either be ignored, understated or simply unknown. In that scenario, the rush to vaccinate yourself and your children might not turn out to be such a grand idea.

Public-health officials around the world seem to be suggesting there is a possibility this flu pandemic could get much worse, that is, become more lethal. If that were to happen, it seems “obvious” that wise people should seek to have a preventive flu shot or access to a pill. Many people will say to themselves: Why not get the shot, just to be sure?

Part of the answer to that question is that until a million people roll up their sleeves to get the vaccine, no one can be sure how safe it will be. This is also a decisive answer to those who favour making vaccination mandatory.

Some public-health officials have described flu vaccines as “highly effective,” but the internationally recognized Cochrane Collaboration (which accepts no money from the pharmaceutical industry) did a systematic review of all high-quality randomized trials (25 in all) studying influenza vaccination. They concluded that “the evidence does not support universal immunization of healthy adults.” Period.

So how does this information help us to think clearly about the current flu pandemic in which we're mired?

Well, it seems that despite its spread, this flu virus is a bit of a dud for the fear-mongers. If, as seems not unlikely, the H1N1 virus mutates, our government will have purchased enormous quantities of a flu vaccine around which we will have virtually no safety or effectiveness data, and an already existing and very costly stockpile of probably useless drugs.

In short, a big bust all around.

Governments and public-health officials are sensitive to the exhortation: Don't just stand there, do something. But it's sometimes wise to reverse that dictum: Don't just do something, stand there (and think a bit about what might actually produce more good than harm).

Alan Cassels is a drug policy researcher at the University of Victoria. Arthur Schafer is director of the Centre for Professional and Applied Ethics at the University of Manitoba.

More link - www.reflections.com.hk