Carbohydrate-based vaccines constitute successful therapeutic arsenals against microbial infections, particularly since the advent of bacterial capsular polysaccharide (CPS) protein conjugates. These prophylactic approaches are increasingly more accessible for other therapies such as viral, parasitic, fungal infections and even against certain forms of cancer. Three major discoveries are responsible for rapid growth in this field. In the first instance, the recent commercialization of the first semi-synthetic vaccine against bacterial infections caused by Haemophilus influenza type b, second by the rapid access to complex saccharide structures through one-pot, solution-phase syntheses, and third by automated solid-phase synthesis.: