I took my two-year-old to the doctor today for a persistent cough, and while in the waiting room I overheard this nugget from an old woman to her friend:

‘They want me to have the flu jab but I said no. They’re very bad for you. Last time I had it, it gave me the flu. And they’ve got mercury in them. No thank you very much!’

The irony is strong with this one…

I’ve already discussed the belief that MMR causes autism (it doesn’t), the health benefits of amber necklaces (none), and the efficacy of homeopathy (zero), so I might as well bust some myths about the flu jab while I’m at it.

1. They give you flu

No, they don’t. While some ‘live’ vaccines give you a small dose of a virus in order to build your immunity as your body fights it, the flu jab isn’t one of those. Instead, it gives you inert, inactive parts of the virus – enough for your body to recognise it and start producing antibodies against it without risking being infected by it.

Of course, there’s no guarantee that you won’t still catch the flu from another source, because there are hundreds of different strains of the virus and it’d be prohibitively expensive to vaccinate against all of them. Instead, the way the vaccination program works is that the World Health Organization (WHO) identifies how many people are infected by each strain around the world and therefore the most likely strains to infect people in the coming season. For the autumn jabs, the strains are identified in February, and then national bodies decide which of them to vaccinate against and spend six months making it. It’s not foolproof, but it’s the best system we’ve got.

2. They’re bad for you

No, they’re not. You know what’s bad for you? Flu. True, the flu jab can give you ‘flu-like symptoms’ for a couple of days – muscle aches and a mild temperature – but influenza is a far more serious illness. It’s much worse than a ‘heavy cold’. The ‘Spanish flu’ pandemic after the First World War infected 500 million people and killed between 50 and 100 million. Even today, in the UK it’s estimated that more than 600 people die of flu each year, rising to more than 10,000 in some years, mostly from vulnerable groups like young children and the elderly.

Furthermore, there are three main types of flu: A, B and C. Type C is the mild form that many people might catch and think, ‘Hey, that wasn’t so bad.’ If they catch either of the other two, they wouldn’t be so dismissive.

3. They contain mercury

No, they don’t. Oh, you’re talking about thiomersal? Still no. Thiomersal (or thimerosal) is a mercury-containing preservative used in some vaccines to prevent the growth of bacteria and fungi, but only in multi-dose vials. Other than some very rare cases, the flu jab is provided in single-dose vials or pre-filled syringes. Since these are sealed units, they aren’t vulnerable to contamination and therefore don’t need thiomersal. So, no mercury.

And even if they did contain thiomersal, you’re getting worried about the wrong kind of mercury. Thiomersal contains ethylmercury, an organic compound that has never been shown to cause any harmful effects to humans and remains in the blood only a few days before the body excretes it. The type to worry about is methylmercury. That’s the kind that’s toxic to humans, builds up in our bodies over time and is contained in certain fish.

‘But how can mercury be safe? It’s a metal,’ I hear you cry. So is sodium, and chlorine is poisonous, but put them together and you get sodium-chloride, aka salt, which we need to survive. This is chemistry. Substances in compound change the properties of the individual elements.

4. Doctors are evil

Underlying this entire hysteria about MMR causing autism and flu jabs containing mercury and causing flu is the idea that doctors are evil. The drug companies know it’s bad for you, but they do it anyway because they’re chasing the Almighty Dollar, and your doctor is complicit in hiding this awful truth because they’re getting kickbacks from Big Pharma. It’s all a global conspiracy.

Most conspiracy theories are full of holes so big you can drive a truck through them, like that 9/11 was an inside job or that someone other than Lee Harvey Oswald shot JFK, but this one is particularly stupid. While it’s true that ‘Big Pharma’ have some pretty questionable ethical standards, and certain doctors are less than trustworthy, is it really likely that every doctor, biologist, biochemist and pharmacist on the planet is carrying out a vast evil upon the whole of mankind? Does every child who grows up with the philanthropic idea of helping people turn into a Machiavellian monster as soon as they set foot in a medical school?

For crying out loud. I watched an episode of Rawhide called ‘The Incident at Red River Station’ which was about exactly this soft of thing. A doctor was trying to vaccinate a small town against smallpox. The townsfolk, a crazed mob with burning torches, called him a witch doctor who was trying to infect them. They instead wanted to rely on their traditional cures of leeches and herbal tea. The result? A whole bunch of them caught smallpox, and it was too late to do anything about it.

This episode was set in the 1860s. It was broadcast in 1960. Are we still going to face this crap in 2060?