Neonatal herpes simplex virus infection.

The incidence of genital herpes simplex virus (HSV) and neonatal HSV infection is increasing in the United States. The risk to the neonate of a woman with genital recurrences (1%-3%) versus first-episode infection (30%-50%), even when asymptomatic, has been defined. Appreciation of the subtle clinical signs, as well as more obvious cutaneous signs of neonatal infection, will lead to appropriate diagnostic evaluation (including, at times, polymerase chain-reaction assay) and therapy. Understanding the immune defects predisposing the neonate to severe HSV infection will enhance efforts to reconstitute the neonate's immune function. Maternal vaccination, chemoprophylaxis, and appropriate use of cesarean-section delivery may prevent cases of neonatal herpes now and in the future.