I've done some research on your question. Please be aware of the
following important disclaimer: "Answers and comments provided on
Google Answers are general information, and are not intended to
substitute for informed professional medical, psychiatric,
psychological, tax, legal, investment, accounting, or other
There are several different forms of the flu vaccine. I think the very
best thing for you to do is to determine the manufacturer of the
vaccination you received and contact them for information on receiving
a duplicate injection. They may suggest that you wait a certain
timeframe before trying to get another shot or be able to provide you
with information specific to their vaccine.
I found an article on HealthLink (Medical College of Wisconsin) where
a physician answers health-related questions from the public. Someone
asked a question very similar to yours:
"Q: I took my dad, who is 89 and very forgetful, for a flu shot last
week, only to find out that he'd already had one the day before! Could
any harm come to him from having two shots so close together?"
Excerpt from Answer: "Contrary to what some people may think, the flu
shot has only non-infectious viruses and does not cause flu. I don't
expect your father will be any the worse for having two shots."
The full article can be found here:
I also read that in young children, flu shots are given in two doses
one month apart. "The two doses of vaccine help the childs body make
strong protection against influenza."
That article can be found here:
I hope that helps to answer your question. If you're ever in doubt,
always consult your physician or contact the manufacturer of the
vaccine for more information. Please let me know if I can be of
further assistance on this question. Thanks!