Recurrent asymptomatic viral shedding accounts for most of the oral, sexual and neonatal transmissions of herpes simplex infections (HSV). In immunocompetent individuals asymptomatic shedding, as determined by culture, occurs during 2-8p.100 of days, and more for persons with HIV infection or if measured by PCR. Antiviral therapy dramatically decrease but does not eliminate asymptomatic shedding. The main risk of HSV transmission to the neonate is during vaginal delivery from infected asymptomatic mothers who acquire HSV genital infection late in pregnancy. Because the survival of HSV out of the oral-genital secretions is weak, indirect and/or nosocomial transmisions of HSV are very rare and should be controlled by common-sense precautions. The prevention of the acquisition of genital or neonatal HSV infection is a challenge because it is based on the understanding and the control of asymptomatic shedding.