Abstract: The invention concerns treatment of infectious and tumoral pathologies comprising a anti-infective and/or anti-tumoral chemotherapeutic treatment phase inducing resistance mutations and a therapeutic vaccination phase directed against said resistance mutations and the agents used in said treatment More particularly, the invention concerns peptides of 8 to 80 amino acids of the HIV reverse transcriptase sequence and comprising at least a mutation with respect to said wild sequence of said enzyme, mutation induced in response to treatments by nucleoside and non-nucleoside analogues of the HIV reverse transcriptase. The invention also concerns a pharmaceutical composition or vaccine based on said peptides, for inducing an immune response specific of said mutated sequences and for enhancing or prolonging the efficiency of treatments with nucleoside or non-nucleoside analogues of the HIV reverse transcriptase.