Outside the cell it is the immune system that handles viruses. Inside the cell there are only two possibilities: either virus kills the cell by lysis or part of it is incorporated into the cell DNA and cell is protected from similar viruses ( Lysogeny). As for RSV, please see presentation from Professor Zajicek on you-tube: "How to cure chronic Hepatitis, In 1911 Francis Peyton Rous discovered the Rous sarcoma virus (RSV) which
causes a chicken sarcoma. In 1960 Harry Rubin discovered a virus which prevents RSV from causing a chicken sarcoma, ..."