Antivirals complement vaccines in combating virus infection.  They may have a role in prophylaxis (in addition to vaccines) to prevent infection as well as therapeutically to treat disease.

Despite enormous efforts to develop antivirals against a variety of respiratory virus diseases, relatively few have proved to be clinically effective and few have been licensed. In some cases this has been due to the mild nature of the disease, the narrow spectrum of antiviral activity or the ease of resistance emergence.  Most success has been achieved with influenza with licensure of antivirals against two targets, the virus M2 proton channel and neuraminidase.

Antivirals are usually selective inhibitors of virus-specific processes which interfere with virus replication and either prevent or reduce infection.  They include a spectrum of agents, from small molecules (e.g. amantadine), to peptides, to antibodies (e.g. palivizumab).