Hi Mr. Shiro,
Sorry, this pc is english only available!
In my case, I took the vaccine of yellow feaver in Tokyo, then went to Kenya and Tanzania, so I have no idea whether you will be able to take the vaccine in foreign countries which you will vist.
However, whenever entering some countries such as east africa, you MUST have a vaccine.(I've heard some parts of Brazil as well.)
Therefore, I strongly recommend you should take that. It is not expensive compared to stay a hospital if you gotta the disease.
In addition, you should pay attention to MALARIA!
I actualy gotta it in Kenya, and spent really hard days. (My weight had reduced 5 Kg for just 2 days)
These above does not answer your question, but taking vaccine is really needed anyway.