Long-lasting coexistence of HIV-1 replication with host immune responses in VNPs is expected to lead to a continuous Env escape from neutralizing antibodies and accumulation of mutations to compensate cost in viral fitness29,30, while in RPs viral replication occurs in severely immunocompromised individuals favoring uncontrolled HIV-1 replication and selection of the fittest variants, as described for late AIDS phase of chronic infection31. The gene discussed is ERVW-1; the disease is AIDS.