Hundreds of people wait in line outside a health clinic in Elmsdale, N.S. for their turn to be injected with the H1N1 flu vaccine. (Andrew Vaughan/Canadian Press)

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Alan Cassels is a drug policy researcher at the University of Victoria and co-author of the 2005 book Selling Sickness about the role of the pharmaceutical industry in helping to create and market illness. These are his responses to questions he has been getting regularly these past weeks via email and from anxious parents in the schoolyard about the H1N1 virus and the vaccine that has been designed to deal with it.

Q: Should I get vaccinated or not? Young people are dying from this flu, surely the vaccine might help?

A: It largely depends on your own situation. If you are the kind of person who routinely gets the flu every year, finds yourself missing work, has other chronic conditions or, even, is just plain worried, go ahead. It might help and probably won't hurt.

If you are, like me, relatively healthy, rarely get the flu and don't work in a situation where it might be hazardous to be sick (such as a hospital), then you can probably give it a miss.

Q: Are public health officials fear mongering?

A: Not really. If they didn't push a mass immunization campaign, they would not be doing their jobs.

Yet with the media focusing on deaths in the rare cases, such as otherwise healthy young children, clearly this isn't productive.

Drug policy researcher Alan Cassels of the University of Victoria. (Courtesy Alan Cassels)

Logic and rationality, not raw emotion, should govern our responses.

Q: Is this pandemic worth worrying about?

A: Probably not. If we can learn from the experience in the southern hemisphere, which just had its main flu season, mortality from the H1N1 virus is relatively low.

Most countries had flu-related mortality rates of less than one per 100,000 cases. That's tiny.

Q: But what about the Spanish flu of 1919? Couldn't the swine flu pandemic be a repeat of this massively deadly pandemic?

A: Not likely. It's healthier to think in terms of probabilities, not possibilities.

The Spanish flu had such a high death count partly because it took place in a world without antibiotics and which was much less wealthy and less hygienic than today.

Do we need reminding that in 2005 the World Health Organization predicted that up to 150 million people might die from Avian flu? The eventual death toll was 262 people.

Q: But surely the H1N1 flu is severe and deadly?

A: Compared to what? The regular run-of-the-mill seasonal flu? Nope. There is substantial evidence that the mortality rate from H1N1 flu is actually much smaller than seasonal flu.

Q: Does the vaccine work?

A: It depends on your definition of work. It works in terms of helping people develop antibodies to that particular virus. But are those antibodies enough to keep you from getting sick?

Often people who get the flu shot still get the flu. And we know there are many other circulating viruses that could still make you sick.

When people tell you the flu vaccine "reduces mortality by 50 per cent" you need to know that these stats come from cohort studies, which compare death rates in vaccinated people versus non-vaccinated people.

The truth is, those two groups may be very fundamentally different to start with and the vaccine might have had nothing to do with the observed outcomes.

This "healthy-user bias," as it is called, is rampant in vaccine studies. Without randomization and a true control group to compare, we don't really know for sure if flu campaigns achieve their intended outcomes.

Q: Isn't it public spirited to get vaccinated, so you won't spread the virus to others?

A: That sounds plausible, but is that recommendation evidence-based? Researchers who have combed through hundreds of flu-vaccine studies find very little evidence that suggests a vaccine will prevent the spread of the virus in the general population.

Of the hundreds of studies on flu immunization campaigns, only about four are of sufficient rigour to say anything definitive. And two of those studies show the vaccine in question to be useless.

Basing public health policy on only two quality studies doesn't seem sound to me.

Q: Is the vaccine safe?

A: Again, depends on what you mean by safe. Within the bounds in which it was studied, the H1N1 vaccine appears not to have much of a tendency to produce adverse effects.

The truth, however, is that we don't know of any rare but potentially serious effects of the vaccine campaign until we've inoculated many thousands of people.

Repeating the refrain that the vaccine is "safe and effective" is fine for reassurance but it is starting to sound strained because no one can say with 100 per cent confidence that the new flu vaccine won't cause adverse effects in some people.

Q: What's your bottom line? What needs to be done to eliminate all this uncertainty of the vaccine?

A: More research. Better research in the form of large, randomized, placebo-controlled trials on the annual flu shot would undoubtedly erase some of these concerns and establish where the benefits and harms lie.

Following patients over the long term will give us a much clearer picture of a vaccine's safety and effectiveness and the effects of natural immunity.

To those who say that studying the sacred flu shot with randomized, placebo-controlled trials is unethical, I say that if such a trial were planned, I'd be first in line to roll up my sleeve.

To me, it is unethical to carry on large-scale, hype-inducing public health programs without collecting the kind of good quality data that is needed to prove the vaccines are doing what we hope they are.

Q: Any last words?

A: Here's my sound bite: "If they randomize, I'll immunize." In the interim, government policies of calmness, coupled with accurate information for both professionals and public is my prescription. Hype can make us all ill.