I'm not certain what the current requirements are specifally these days, but, yes, there are required innoculations for Africa. You'll get a yellow piece of paper which is kept in your passport that lists them, and the paper is actually looked at in some countries. It used to be thypoid, small pox, gamma globulin, and maybe one other. Also, if you are travelling outside cities much, you'll be put on a course of malaria preventative which is important to follow through on.
There's also a time period before travel that you need the shots done, so they are in effect when you go, and the malaria medicine is started a couple of weeks before you go and you continue it for a while once you're back.