It is very important to "read" the package insert!!
How many take a flu shot w/o reading before. I would bet very few. I asked a pharmacist for the insert to read and that person did not know what I was talking about?! I said, I will come back tomorrow. I asked the same person and I finally got an insert to read.
Some years ago, a flu shot was known as a 3 parter when in truth it was a 4 parter. The 4th ingredient was "other". It made "true" doctors suspicious enough not to take the shot themselves.
I for one will never, never take a flu shot. Never!