Herpesvirus vaccines: challenges and future prospects

Human herpes viruses are a family of large double stranded DNA viruses. Their life-cycle is characterized by an initial lytic cycle of infection in which large numbers of new virions are generated, followed by a pattern of lifelong latent infection with intermittent reactivation and viral shedding. Co-evolution over millennia has resulted in an interaction between host and pathogen which leads to the successful establishment of a lifelong latent infection with typically minimal impact upon the host, and subsequent maintenance and control of latently infected cells by the host immune system. Infection is usually asymptomatic or leads to an acute transient disease. However more severe disease can arise during primary infection, latency or upon reactivation; in both an immunocompromised and an immunocompetent setting, indicative of a need for the development of vaccine strategies which can either prevent infection or treat virally-associated diseases.