EMAIL! (technically, a paraphrased really great question from someone at FreeOK!)
Is there any reason why I, a young healthy adult, really *need* to get the flu shot every year? Even if I do get the flu, wont that just make my immune system stronger?
Blech. Flu shots. Every damn year people are bugging us to get the flu shot. But no one likes shots. They cost like $10-$20. Have to take off work or run to get one in between classes. And then your arm hurts allllll daaaaay and you might get a headache or a little fever. UUUUUUUGH WHYYYYY????? WHYYYY????
“Do I *have* to get the flu shot every year?” I totally understand where you are coming from.
The answer isnt an easy yes/no.
First, the basic ‘WHY??????’ behind the flu-shot-every-year thing.
Heres the deal, influenza has a couple different ways of changing. The one that probably jumps into your head immediately was ‘Oh, yeah they mutate’. Yup! Influenza is an RNA virus. The enzyme that makes RNA from RNA makes a lot of mistakes. Those mistakes in the RNA genome/messages translates (heh) into variation in amino acid sequences, thus variations in protein structure, ‘antigenic drift‘. Start with Protein A and then you get ‘Kinda Protein A’ and then ‘Kinda Sorta Protein A’.
But influenza is a segmented RNA virus. So if something is infected with +2 different ‘kinds’ of influenza, the viruses can shuffle their genomes. Thats called ‘antigenic shift‘. Start with Protein A and then you get ‘Protein Not-A’.
While influenza has these different sources of genetic diversity, that diversity is under selective pressure from *us*. The human population is generating antibodies to variants of influenza, either from getting sick or by getting vaccinated. This selects out the influenza variants the human population doesnt have good immunity to, so those variants are the ones that infect us the next year, and so on and so on.
We are caught in this evolutionary treadmill because 1) influenza can change a lot, and 2) we cant make antibodies to *one* influenza infection or *one* influenza vaccine that protects us from *all* kinds of influenza.
Thats why scientists were super pumped about identifying antibodies that *could* work on lots of different kinds of influenza.
So, thats why we have to get new shots every year to ‘influenza’– usually every year, the shot is slightly different mix of three influenza variants than it was the years before (sometimes there are duplicates).
To answer the second part of that question first “Wont getting sick rather than getting the shot make my immune system stronger?” The answer is ‘Yes, kind of, but it doesnt matter.”
When you get sick, you make antibodies that are really, REALLY good at attacking the virus you were infected with.
When you get a vaccine, you make antibodies that are pretty good at attacking a virus you might be infected with. Vaccines are composed of crippled/dead viruses or just chunks of viruses– while they train your immune system to fight off a pathogen, its not as ‘robust’ of a training as you get from actually getting sick. So if you compared the antibodies from a person who got sick and a person who got the shot, the person who got sick would have ‘better’ antibodies for that variant of influenza.
But since influenza changes all the time, theres not really much of a point to getting a ‘stronger’ immune response from getting sick. The influenza circulating this year is going to be different from last years– who cares if you got sick last year? The flu vaccine is trying to train your immune system for the *modern* virus, not the one that was hanging around last year.
On to the first part of the question– “Do I need to get the shot every year?” Well, it depends on who you are and who you are around.
In these cases, your decision to not get a vaccine could kill or seriously harm someone else (I might be forgetting some):
- Did you/a relative just have a baby? You better get the shot to keep you from infecting baby.
- Do you hang out with your grandparents a lot? You better get the shot to keep you from infecting Grandma and Grandpa.
- Do you hang out with someone who is immuno-compromised? If you are around anyone who has to be on immuno-suppressive therapy for a medical condition or is otherwise immuno-compromised, you better get the shot to keep you from infecting them.
- Are there extenuating circumstances? Sometimes something non-normal happens, eg Swine Flu. If something weird pops up like Swine Flu, or a flu that is differentially affecting ‘young healthy’ people as opposed to the normal ‘very young’/'very old’ groups, then you better get the shot.
In these cases, your decision not to get a vaccine might not be so dramatic:
- Are you a student? Schools, gyms, and dorms are warm, moist petri dishes. If one person gets sick, EVERYONE gets sick. If you dont want to be part of that, if you *cant* miss class or the district basketball finals, you better get the shot.
- Can you afford to get sick? Can you afford to miss work/household duties for a week? Can your business/household afford for you to be out of commission for a week? Can you afford the potential medical complications that could arise from ‘only the flu’? This might be something those of us in work-a-holic-no-healthcare US people think about, but it *is* something that I weigh when I am debating ‘do I need to get the shot this year?’
These lists are non-exhaustive– People might bring up more situations in the comments.
But my point is, there is no inherent ‘benefit’ to getting sick from influenza. There is no reason to get sick from influenza. We have a vaccine. Yeah, sometimes we gamble wrong when guessing what strains to put in the influenza vaccine, and you might get sick anyway, but any way I can stack the deck in my favor, towards ‘not getting sick’, Im going to do it.