Intra-uterine and neonatal herpes simplex virus infection.

Herpes simplex viruses type 1 (buccal) and type 2 (genital) present a serious threat to neonates. Infection may occur in utero, by transplacental or ascending infection, by exposure to genital lesions during delivery, or postnatally from relatives or attendants. Antiviral drugs, vidarabine and acyclovir are of equal efficacy and toxicity when used in infants with herpes simplex infections. Transplacental infection during early pregnancy is a very rare cause of congenital abnormality but there have been no recommendations for intervention. Most neonatal infections are acquired from the mother during delivery. Antepartum screening for virus excretion is of no value in predicting exposure at delivery and should not be performed. Caesarean section should be reserved for women who have active lesions at delivery. Even if active lesions are present, in women with a history of recurrent herpes, the risks to the infant are low. Prophylactic acyclovir during pregnancy cannot be recommended until evidence of safety and efficacy has been obtained from controlled trials. Staff should be alert to the dangers of postnatal infection and measures should be taken to exclude, or reduce virus excretion from, staff members or visitors who have orolabial or cutaneous herpes lesions.