Why are antibiotics not effective for viral diseases?

Antibiotics are effective against bacteria and other non-viral pathogens as they block some of their biosynthetic pathways without affecting human beings. However, viruses do not have their own metabolic machinery. There are very few biochemical processes that can block viral multiplication. Antibiotics are not effective against them. They can be overpowered only by development of immunity against them, by the body the host. An antiviral product, called interferon is produced by the cells exposed to the action of virus.