By Daliah Wachs, MD, FAAFP
Every year I hear “I won’t get the flu shot ever again because it gave me the flu”……Does this really happen?? Can you get the flu from the flu shot?
The answer is “No”, but the topic is definitely worth dissecting.
Firstly, the flu shot is made up of an “inactivated virus”. A nice way of saying a “killed virus”. Although the nasal spray version of the flu shot is a watered down, weakened version of the virus, the flu shot does not have active virus in it. So technically you cannot get the flu. Rarely someone could have an allergic reaction to the shot and scientists are investigating the incidence of neurological conditions such as Guillain-Barr�© and narcolepsy. Again these are rare and would not feel like “the flu”.
But, many of you say you came down with the flu after receiving the flu shot. Why?
For one thing, many of you are getting the flu shot too late. Influenza starts to circulate in your neck of the woods and you are exposed before the shot gets a chance to prime your immune system.
Secondly, the flu shot is not 100% effective. The average efficacy of the flu shot is approx. 60% but can be better in certain populations. Moreover the flu shot usually protects against 3 or 4 strains of the flu. You could be exposed to a strain of the flu that was not in this years flu shot, hence coming down with the “flu” after receiving your flu shot.
Finally, what could be occurring is, the flu shot starts to work by inducing your immune system to recognize the flu and this activation of your immune system makes you feel some of the symptoms of the flu.
So for those of you afraid of getting the flu shot, discuss with your provider about what your concerns are and what symptoms you came down with in the past. It might not be the flu shot after all.