Meningococcal Vaccine

Hi,

I will be a freshman next year in college and after sending in my health records, my school recommended me to take the Meningococcal(Menactra) vaccine. However, I've already had a vaccine in 1996 (when I was 5 or 6) that's qualified as "Quadrivalent polysaccharide (Menomune) outside of the country. When I asked my doctor about a month ago, she said that I probably don't need it since the need for booster is unkown. Now that I had did more research on the disease, I read "up to 11% can carry it without symptoms at one time" and am quite worried. Also, my insurance is out and my school's insurance doesn't cover the vaccine, which is over $100. I'm wondering if I could get more advice on whether I really need it or not. Thanks.