By Tom Jefferson, Cochrane Collaboration

Welcome to Facts about flu – Our week-long series of articles about influenza.

The answer is complex but, strangely, it hasn't much to do with viruses, bugs and other nasty things lurking in dark cupboards.

Here are a few facts.

The surest way to create a market for lotions and potions is to create a need for them. You do that by either ramping up an existing problem or manufacturing a brand new one that fits the indications for use of your lotions and potions. In our case, there's a bit of both.

Syndrome or disease?

The flu, as its commonly known, is not a disease: it is what is known as a syndrome. A syndrome is a series of signs (like cough) and symptoms (like feeling knackered, or having aches and pains) caused by a variety of agents.

The flu comes around every year but only a small proportion of flu episodes can actually be ascribed to influenza viruses. Around 7% to 10% of flu episodes are influenza “on average” i.e. averaged over a six-month period.

The vast majority of flu episodes are either caused by other viruses (you've probably never heard of them but here's a selection: metapneumovirus, rhinovirus, respiratory syncytial virus) or have no recognised cause. You can't tell what is causing what, when, where without lab tests, which are expensive.

These lab test are also, by and large, useless for practical purposes because even if you wanted to know what is going on, by the time you get the answer you are feeling a lot better, thank you.

And here's the trick: the public don't know this. To them, all flu is influenza and vice versa. So the easiest way to create a need is to blur the distinction between the two, making folk around the world believe that when they're watching Google's flu tracker, they're watching the progress of influenza.

They are not.

Great public health bodies, such as the US Centers for Disease Control and Prevention (CDC), are very good at doing this as their abuse of this f-word shows.

Claiming the deaths

Next come models. If you were to ask how many certified influenza deaths took place in Walkabout Creek in, say 2010, you would get one of two answers: don't know, or a very low number.

Influenza-related deaths are extremely difficult to ascertain for a complex series of reasons, including the impossibility of distinguishing flu-related from influenza-related deaths. Like with all forms of flu, to be able to tell them apart you need tests or, if you're dead, a post-mortem. That's probably not something you agree your grandad's body should be subjected to in order to please people like me.

So enter models, a complex alchemy of bits of data on the circulation of certain viruses (never mind the others), past certain influenza-deaths figures, and all sorts of deaths from different causes (now even heart attacks), which are deemed by the modeller to possibly be influenza related.

This is why when death figures are quoted in official documents, a range of estimates is always reported. With models, only one thing is certain – that the modeller can prove or disprove anything you want.

Now you'd think that, like packets of cigarettes, all these warnings from the World Health Organization (WHO), CDC and other such worthies and all the recommendations for lotions and potions would come with a warning about the validity of the data on which they are supposedly based. Think again.

The icing on the cake

The finishing touch for creating our market is to get academia, public health agencies and the media so involved in the issue that they are unable (and, in some cases, unwilling) to look critically at what is going on, to think outside the box.

An even better move is to get decision makers to make policy and police it. This guarantees unsolvable conflicts and a passport to no change of policy, even in the absence of any valid data to support it.

In the early 2000s, WHO's policies were written by a selected group of outside influenza experts. These had and still have very close ties with industry. They are known as key opinion leaders. There's loads down under, too.

Not all key opinion leaders are pharma creatures; some actually believe what they say. But what they do consciously or unconsciously is spin the message as I have described.

In Canada, very powerful key opinion leaders introduced a policy in late 2012 for health-care workers to get vaccinated against influenza, or wear a mask with a badge declaring their status of hazards to the community, or be sacked. Attempts at coercion may be on the way down under, too, and you should be vigilant.

Slice of disbelief

I am sure you've found all this absolutely extraordinary and probably unbelievable. If you did, go ask your local public health body what the influenza casualty rate in Walkabout Creek was in a period of your choice.

If they answer, and answer with a range of figures, ask them why there's a need for a range. And if the answer is I don't know or it's very difficult, ask them how they know influenza is a threat.

I'll leave you with one more fact.

The best scientific evidence on whether influenza vaccines work comes from healthy adults, the group that least needs protection and that can mount the best antibody response to the virus without help.

Here's what happens in the most-optimistic-possible scenario when the ever-changing influenza viral configuration closely matches that contained in the vaccine (which happens one year out of two, on average):

You need to vaccinate 100 health adults to prevent three cases. That means cases with sets of symptoms, not death or pneumonia, and there's no good evidence that they do that.

Other pictures and the complete relevant evidence reviews can be here.

This is the first article in our series Facts about flu. Watch this space of more.

TJ has published on influenza antivirals and received a UK National Institute of Health Research Grant funding for the update and amalgamation of two Cochrane Reviews: neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. TJ receives royalties from his books published by Blackwell and Il Pensiero Scientifico Editore, none of which are on influenza. He is occasionally interviewed by market research companies for anonymous interviews about Phase 1 or 2 products. He was a consultant in a legal case regarding oseltamivir and is a now acting in a legal case on influenza vaccination on behalf of healthcare workers's uninons in Canada. TJ consulted for Roche 1997-1999 and Sanofi Synthelabo in 2004.