Viruses are infectious particles comprising a nucleic acid core & consisting of either DNA or RNA – and a protein coat known as a capsid. Infections attributable to viral pathogens are transmitted, directly or indirectly, from one person to another or from animal to human. Viruses replicate by exploiting the resources of their host cells, usually to the detriment of the host. As viral pathogens are exceptionally diverse, the morbidity associated with viral infections varies significantly depending on the virus in question. This report covers all viral infections, although particular focus is given to four key indications within this disease cluster: Human Immunodeficiency Virus (HIV), Hepatitis C Virus (HCV), Hepatitis B Virus (HBV) and influenza. The global viral infections market was valued at $74.0 billion in 2014, and is projected to grow at a considerable Compound Annual Growth Rate (CAGR) of 6.8%, reaching $117.6 billion in 2021. Key drivers of this growth will be the expanding treatment population and uptake of recently approved highly priced antiviral agents, as well as promising late-stage candidates that are expected to be priced highly.