A few years ago I got the Typhoid Fever shot because I was going to be traveling to some third world countries. 1 month after I had the shot, I went on vacation and became violently ill. The doctors told me that based on my symptoms (high fever, headaches, stomach aches, bloody diarrhea, no appetite) it was typhoid fever and treated me without testing me. months later when I finally got home from traveling, I was tested for Typhoid fever, and I responded positively to SALMONELLA O, TYPE Vi with somatic (O) antigen antibodies. My question is, how do I know for sure that I did have Typhoid fever (and that the positive test wasn't the result of my earlier vaccination)? Is there some way to know for sure the antibodies I had in my system were from the actual disease and not the vaccination? (I'm a little concerned, because if it wasn't actually Typhoid, what could it be that I had?!) Wasn't my vaccination supposed to prevent the Typhoid? What are the chances someone can get Typhoid even though they were vaccinated? Does this mean I can get typhoid fever again (do I need to be vaccinated again?)