Vaccination

I was vaccinated this morning for Hepatitis A, in preparation for my upcoming trip to Russia. I also got some Typhoid vaccine pills, which are a bit expensive at $10/pill. Thankfully, it only takes four to vaccinate you. I asked the doc if I needed to get Hepatitis B as well, and he told me no, since I wasn't going to be having unprotected sex or getting a blood transfusion while in Russia. How does he know what I'm going to do there?