Over at reddit, a physician writing under the pseudonym of /u/crucifoxes (a throwaway account which will not be used again) provides a concise summary about the medical reality of flu shots. This is a crucial read for anyone who has questions, and – from where I sit – helps clear up a lot of the tinfoil-hat nonsense that swirls around vaccinations in general. It deserves to be shared; I have bowdlerized it only slightly, and any emphasis is mine. The answer arose to the following question in /r/Vancouver: “I have never gotten a flu shot before, this year I have the option of getting one for free but I’ve heard both negative and positive things about getting them. Do you get one? Why or why not?”
Physician here. If I were you, I’d jump at the chance for a free flu shot.
The reason there are so many misconceptions about the flu shot is largely due to the lay public’s understanding of Influenza.
We have taken to calling any stomach bug or upper respiratory infection “a flu.” Stomach flu. 24 hour flu. Et cetera. It’s all nonsense. There are hundreds of mild viruses that cause these symptoms, none of them are Influenza, and none of them are meant to be reduced by getting the flu shot. So when your aunt Kathy complains that her flu shot didn’t work because she threw up for two days in February, slap her gently across the face. That wasn’t flu, Kathy.
I’ve had Influenza A once in my life, and once was enough. Two weeks of headache, myalgia, nausea, vomiting. Every day it felt like I had just woke up after being hit by a bus. I will never, EVER call any cold-with-some-squirts a “flu” anymore.
Now. With that established, we still haven’t really figured out if you should get the shot or not.
Advantages: Lower chance of acquiring Flu, maybe a less severe course if you do contract the infection.
Disadvantages: sore deltoid for a day or two, maybe a mild cold-like illness for a few days.
That’s essentially it. There’s a lot of polemic out there around vaccines, but most of it is hogwash, and the rest is mostly outdated concerns about chemicals that aren’t used any more.
The flu vaccine contains no “live” virus whatsoever, nor does it contain any flu DNA. You cannot “get the flu” from a flu shot. What you can get is some side effects of your body mounting its immune response, hence the cold-like symptoms listed above.
The flu vaccine does not contain thimerosal (exception – if you’re a senior citizen, they’ll still give you the thimerosal-containing vaccine. This is because you’re old, your immune system isn’t exactly top-notch anymore, and the addition of thimerosal helps potentiate the immune response. If you don’t know what I’m talking about, don’t worry about it. Don’t even Google it. There’s about as much evidence for vaccine levels of thimerosal being harmful, as there is evidence for wifi signals being used to control your mind.)
Some haters will also bring up rare, 1:1 million complications, like Guillain-Barre Syndrome. This condition is ultra rare, can occur with any viral illness or immune response, and is actually MORE likely if you get the flu than if you get the vaccine. The risk of dying if you catch flu is 1/10000. The risk of Guillain-Barre if you get the vaccine is 1/1,000,000. So you do the math.
That said, if you’re a young adult who is immunocompetent and is not pregnant, your chances of serious disability or death from influenza are pretty low. We encourage vaccination of medical staff NOT because we’re worried about the health of our workers. We vaccinate medical workers so that they are less likely to contract flu, and then kill off half a geriatric ward when they spread it.
I don’t know why you have access to a flu shot, but if it’s because of your own health issues or health-related employment, it’s a no-brainer. Get it. If you’re not in a risk group, or around risky individuals, it’s less clear what your choice should be.
That’s all I got. Keep in mind that while I’m a medical professional, allergy/immunology is not my area. Now go do some decent Googling and then decide for yourself!
EDIT: Forgot about Flumist, thanks for all the reminders. I’m OBGYN so I never use it, my comments are valid only for the non-Flumist, injectable, protein-capsid-whatever types.
At my previous job, I’d get a free flu shot every year, and never once had a negative reaction. I’ve only gotten one since I retired in 2006; I think my insurance covers one annually – I need to check. Now that I’m moving toward bona-fide “senior citizen” status, I think it behooves me to get back in the habit.
The Old Wolf has spoken.
 Thimerosal is a mercury-based preservative, and the biologically inactive form of mercury. It was added to vaccines to prevent the vaccine from spoiling, and to prevent cross-contamination. In the early days of vaccination the whole class was vaccinated from a single bottle with a single needle. Just a quick wipe with a cotton ball and some alcohol.
Thimerosal probably saved many, many lives.