These results thus confirmed the strong potential of DNA vaccines against Leishmania, but also indicated that in most cases only partial protection was achieved. Prime-boost immunization protocols have been tested with various antigens to increase vaccine potency (Table 1) . They are based on priming the immune response with a DNA vaccine and boosting with the corresponding recombinant vaccine based on recombinant virus or protein (Table 1) . In some studies, such immunization protocol resulted in increased immunogenicity of the vaccines and better protection levels [26, 27] , but in others, DNA only remained the best formulation for optimum efficacy [32] . Nonetheless, a major drawback of such vaccine formulation remains its complexity, which may limit their practical use.