Hepatitis
You should be protected for Hep. A and B, you can get a combined vaccine (Twinrix). You never know what will be in your ice cubes..... This goes for all countries with water problems (potable water is scarce), not just the DR
You should also get tested for Tuberculosis (TB) IF you stay for more than 6 months. Although most aren't contagious, you can be carrying the virus without knowing it and it can surface up to 20 years later. It is just a little injection at your travel clinic upon return (don't get tested while you are still in the DR)...
We were there almost 2 years, and half of us came home infected....
Malaria isn't a big deal, unless you go in infected areas (mostly isolated places along the Haitian border, and the eastern part of the country), so the tablets are NOT recommended....