Fewer Flying F's for Fighting Flu's

Dear Doctor Ninja,

Are flu shots part of the anti-vaccination movement? After my social media post yesterday about my 5 year old and I getting our flu shots, I've heard from pro-vaxxers, anti-vaxxers, and people who give flu shots separate consideration from vaccines. What's the story?

P. Rick

To answer your first question: Yes. Flu shots are vaccines and therefore would not be supported by people taking an anti-vaccination stand.

But what is the story?

Throughout modern history, there have been outbreaks of viruses. The symptoms we think of as the flu are caused by many different viruses. The outbreak of 1918, in a time before we even knew influenza was caused by a virus, it’s estimated that 500 millions people caught the spreading strain (thought to be the H1N1 strain) and that 50 million people died from it.

Since the flu is caused by viruses, there are very few treatments to cure it once you have it. Anti-viral medications help, but usually only shorten how long you have symptoms and sometimes make the symptoms less.

Since so many different viruses cause the flu, a flu vaccine can’t protect you from all of them. Every year, public health scientists and doctors (for instance, at the CDC in the USA) look at the information about what flu viruses have been circulating the most. They then make an educated prediction about which viruses will be the most common in the up-coming flu season, which usually runs Fall to Winter and vaccines to those predicted viruses are produced. Since it takes 6 months to mass-produce a vaccine, they have to commit to the prediction by February or March before the fall (September/October) in the Northern hemisphere, and September or March before the fall (February/March) in the Southern hemisphere.

As the saying goes, “It’s always twelve o’clock somewhere,” which means it’s also flu season twice a year globally. Since each flu season runs for almost 6 months, that means it’s almost always flu season somewhere too.

The most common question posed about the flu vaccine is usually, “Why did I still get the flu even though I got a vaccine?”

First off, you can’t tell you’ve been protected against things you can’t see. So while you might have gotten the flu last year, it’s difficult to tell which virus you got and whether you were _also_ infected with one of the viruses that were in the vaccine last year where you didn’t get symptoms.

Secondly, since you can’t be vaccinated against _all_ flu viruses, you can still get “a flu”, just not from the viruses you had a vaccination for.

Thirdly, there are some viruses that are difficult to make vaccines for. When these types of viruses are the predicted viruses, even if the prediction is right, it can be difficult to make an effective vaccine against them because of limitations on vaccine creation and production technology.

Lastly, sometimes, the prediction is off. You’re vaccinated and protected, but not against the viruses that are the most common in your area of the world.

So the reason why some people give flu vaccines a different consideration from other vaccines is this uncertainty. There aren’t a lot of different kinds of germs that cause tetanus. There’s not much guesswork in creating a tetanus vaccine. Therefore, if you were properly vaccinated against tetanus, it would be nearly impossible for you to get lockjaw if you were exposed to the tetanus bacteria.

So why get a flu vaccine at all?

When the weatherperson tells you it’s going to rain, you bring an umbrella because you don’t want to get wet. Even if it doesn’t rain, you’re ready. And sometimes, even though you have an umbrella, it rains sideways, so you still get wet. Or, it hails golfball-sized hail, and the umbrella isn’t really that useful.

One reason to get the flu vaccine is to protect yourself against the predicted viruses that cause the flu. And if you’re in a category of health where getting the flu is potentially a disaster (like young children, or the elderly), then an umbrella even on a day where it might not rain is a pretty good idea.

But other reason to get the flu vaccine is if you’re around other people where getting the flu is potentially a disaster. The thing about the flu is that you can pass on a flu virus before you feel sick. If you’re immune to the dominant virus in your area, you’re much less likely to pass it on. You’re a virus blocker. You break the chain for that virus. Which means you protect others who are either unable to protect themselves, or aren’t as good at it as you. You’re like the person who doesn’t forward email from Nigerian Princes to your friends and tells your mother to stop doing that.