Because I am not an idiot I am a big fan of vaccines, one of the greatest creations of humanity – but that doesn’t mean they lack drawbacks.
The flu vaccine is particularly iffy, because influenza is a multi-faceted disease that changes shape every year. The long advance lead time on creating vaccines means that sometimes the vaccine isn’t terribly effective, as happened two winters ago. (The CDC has a good summary of how flu vaccines are designed and made here.) I get a flu shot every year because it’s more likely to help than not, and because I am edging close to what are euphemistically called the Golden Years. When I do get sick it lasts longer and hurts more, so there’s more value to avoiding illness.
But there’s another concern about flu vaccines: Some people say they can give you the flu, or cause flu-like symptoms. This seems a logical fear, since a vaccine works by tricking the body’s immune system into reacting by putting “dead” flu virus or bits of live viruses into our body, and “having the flu” is mostly the result of the immune system’s reaction to the virus.
I got a flu shot Tuesday at work, and on Wednesday I felt like crap: I was shivering when the house wasn’t cold, I was ache-y, and really tired. It felt like I had a mild case of flu. I slept 10 hours last night and feel better today, but it sure seems like the flu shot gave me a bit of flu.
The CDC says no, pointing to randomized trials in which people give placebo flu shots had the same amount of flu-like symptoms. As further evidence on the “no” side, I have gotten flu shots for years and never had a similar response before. And Tuesday was primary election day so I worked late after getting the shot, driving my long commute home at 1 a.m. whereas usually I’m in bed by 10. The sickness could easily have been my body reacting to fatigue or job stress – I don’t shrug that stuff off the way I used to.
But doggone it, it sure felt like correlation (flu shot one day, flu-ish the next) implies causation. If I was suspicious of vaccines, that could easily lock in an anti-vax certainty to the point that no evidence would ever overcome it. Personal experience trumps outside data, every time.
I’m not suspicious of vaccines because the evidence points that way, but even so it feels weird that I got sick. I admit I’ll be a little bit nervous next year when I get my flu shot.