ERVW-1 and influenza: In conclusion, our collection of data, obtained from experimental assays and from clinical samples, brings new suggestions that HIV-1, through mature virions or its envelope protein, may reduce the replication and delay the evolution of A(H1N1)pdm09 virus, thus contributing to attenuate the clinical course of Influenza in HIV-1/A(H1N1)pdm09 co-infected patients.