ABSTRACT
Most subjects infected with HSV-1 or HSV-2 remain asymptomatic and are unaware that they have been infected or that they may be transmitting the virus. The prevalence of HSV-1 and HSV-2 infection increases with age and varies considerably worldwide (1). In the United States, approximately 85% of individuals become infected with HSV-1 and 25% with HSV-2 over their lifetime. If infection were asymptomatic in everyone, we would have no need for a vaccine. However, HSV-1 and HSV-2 can cause life-threatening, sightthreatening, or emotionally debilitating infections, which explains the great efforts that have been made to develop effective vaccines. Ideally, a vaccine would prevent infections caused by both HSV-1 and HSV-2, and reduce the incidence of both symptomatic and asymptomatic infection. The latter is desirable to prevent transmission of the virus to unvaccinated individuals.
