Herpes simplex virus infection is a lifelong infection. Shedding of the virus takes place even through the intact mucosa of the genitals. However, this is much less than when there is an active lesion. Therefore, the probability of passing on the infection to the partner is also highest during the recurrent active phase. The severity of the symptoms the partner will have, depends upon his/her prior exposure to the virus. If the female gets infection for the first time during pregnancy, then there can be serious problems. The trimester of pregnancy when this occurs, is also an important determinant. Somewhat similar is the fate with cytomegalovirus infection.