Herpes simplex virus vaccines

Abstract

Herpes simplex virus (HSV) types 1 and 2 cause herpes labialis and genital herpes respectively, although genital herpes caused by HSV-1 is increasing in adolescence. Adult HSV-1 seroprevalence in western countries is 55% to 80% (80% in Australia) and acquired in two peaks, in infancy and adolescence. HSV-2 seroprevalence is highly variable geographically, reaching 12% in Australian adults but up to 90% in African countries. After initial HSV-1 or 2 infection, asymptomatic shedding occurs in the mouth and genital tract respectively in nearly all infected subjects. Complications of HSV-1 include keratitis and blindness and life-threatening encephalitis. Severe complications of HSV-2 include acute urinary retention, meningitis and neonatal herpes (25% fatality). In addition, prior infection with HSV-2 consistently enhances HIV acquisition three- to fourfold. In immunosuppressed persons, HSV-1 and 2 may cause indolent ulcers, oesophagitis and pneumonia. Ultimately, a childhood vaccine effective against both HSV-1 and 2 disease is needed.