ERVW-1 and AIDS: To improve the immunogenicity of the NYVAC based HIV/AIDS vaccine candidate, we have developed a novel vector by inserting the host range gene VACV C7L under the control of the synthetic early/late virus promoter into NYVAC-B, a recombinant virus which expresses four HIV-1 antigens from clade B (Env, Gag, Pol and Nef).