Flu shots: Efficacy and effects of the vaccine

Recently, a friend of mine forwarded me a link to a clip on YouTube showing a very bizarre reaction to the seasonal flu vaccination. In it a 25 year old female developed dystonia, a serious neurological disorder, 10 days after getting vaccinated against the flu. How severe was this reaction you ask? Well I’ll let you judge for yourself.

Although it’s impossible to conclude with 100% certainty her dystonia developed as a result of the vaccination, it does appear the vaccination could have been a key contributing factor**.

[**Editor’s note: after a spirited discussion with an MD friend of mine, there seems to be general consensus in the medical community that the wild gesticulations and behaviours exhibited in the video where psychogenic, and not physical, in nature. Even assuming her condition was 100% pyschosomatic, this video serves as an excellent illustration that the placebo effect can result in both positive and negative outcomes.]

Now, I didn’t post this video to cause panic (frankly, 1 person in a million developing a neurological disorder from the flu vaccine isn’t cause for hysteria). But what is more disconcerting about the seasonal flu vaccination program is that the data is underwhelming when it comes to the vaccine’s overall effectiveness.

After watching this video, I did a little research and was able to land some data published in the American Journal of Public Health about flu-related mortality over the past 100 years1.

Flu rates
What I find particularly fascinating is that if you look at the period beginning shortly after World War II (basically from 1950 onward – I circled it in red), the death rates from the flu have changed very little. So clearly, we are doing something to decrease our risk of dying from the flu: the flu shot must work! Except there’s a problem with that thought – wide-spread vaccination with the flu shot really only started in the late 1980s. In fact, amongst individuals 65 and older, vaccination rates have climbed from about 15% in the early 1980’s to over 65% today2. But despite a dramatic increase in vaccinations in the elderly (the group most at-risk for severe complications from the flu), it doesn’t appear that getting the flu shot decreases their risk, or any one’s risk really, of dying from the flu at all.

But let’s be honest, decreasing mortality isn’t the only reason why someone would get a flu-shot. However, the fact the flu shot appears to be wholly ineffective in helping those who need it most, really makes you question its overall effectiveness.

I often see numbers like “80-90%” effectiveness thrown around when discussing flu vaccination success rates. That sounds impressive and suggests that getting the flu-shot is going to keep me healthy this flu season. Small problem though, those numbers only refer to the probability that I’ll produces antibodies to the influenza virus – which may or may not prevent me from becoming sick. What gives then?

It’s important to remember that during each ‘flu’ season, the influenza virus actually only accounts for a minority of total cases of flu-related sickness. For the 2007-2008 flu season in Canada, only about 11% of the total tests of flu symptoms actually came back positive for the influenza virus3. This means that the majority of people who fall ill actually have ‘influenza like illness’ (ILI), to which vaccination is largely ineffective. In a comprehensive review of the effectiveness of flu vaccination programs in healthy adults, the authors found that while flu vaccinations were 75% effective against the flu virus, mass vaccination programs only produced a 16% (at best) reduction in complications from flu-like illnesses4.

I don’t know about you, but I’m a little leery of recommending that everyone get a flu-shot when at best, it might decrease normal sickness by 15%, carries the potential of having severe complications (however minor) and almost certainly doesn’t help the people who need it the most (those at risk from dying from flu complications).

In fact, all of our best evidence suggests that the #1 thing we can do to keep the flu at bay is to maintain proper sanitary practices. You know, all those ‘high-tech’ approaches like hand washing and covering your mouth while sneezing.

Call me an idealist, but wouldn’t we be better off as a society if instead of spending millions of dollars every year on largely ineffective flu vaccine campaigns, we spent a portion of that money subsidizing healthy food for those who need it, encouraged people to get physically active or even suggested people start taking supplemental vitamin D? All of these strategies have potent immune-enhancing properties, result in long-term reductions to health-care costs and carry no risk of complications.

Seems like a no-brainer to me.

Remember, when it comes to what you are doing to your body, don’t accept sub-par advice. I think we all agree, when it comes to our health – “good enough”, isn’t.



1. Doshi, P. 2008. Trends in Recorded Influenza Mortality: United States 1900-2004, American Journal of Public Health, 98, 939-945

2. Simonsen et al. 2005. Impact of Influenza Vaccination on Seasonal Mortality in The Us Elderly Population. Archives of Internal Medicine, 165.

3. Public Health Agency of Canada (Canada Communicable Diseases Report). 2008. Influenza in Canada: 2007-2008 Season Update Canada Communicable Diseases Report, 34(7).

4. Jefferson et al. 2007. Vaccines for preventing illness in healthy adults. Cochrane Database Systematic Reviews, 18.