Herpes Infection

There are actually several “herpes” viruses. What is commonly called “genital herpes” is an infection caused by one of two herpes viruses, either Herpes simplex virus I or Herpes simplex virus II……both abbreviated as HSV. Both of these viruses may be sexually transmitted, and spend their lifetimes travelling up and down nerve pathways close to the site of the initial entry point (usually near the penis or vulva). “Herpes” is common. As much as 10-30% of the U.S. population has been infected.

A “primary outbreak” occurs about a week or so after sexual contact with an infected sexual partner. Localized burning, itching and irritation may be the “prodromal symptoms” which result in the eruption of a painful blister or cluster of blisters. These “lesions” are usually exquisitely painful during a primary outbreak. One may experience swollen lymph nodes in the inguinal area (the crease between the thigh and lower abdomen). Some people feel mildly ill for a day or two. During this time, the virus is present in the bloodstream. The lesions burst open and leave small, painful ulcers which may look like craters. The ulcers heal slowly over a period of 5-10 days.

Some people will have a primary outbreak and never have another herpes outbreak. However, for most people, “recurrent infections” happen periodically. For some, recurrent infections occur almost monthly. For others, a recurrent infection may occur only once or twice a year. Usually the symptoms of a recurrent outbreak are not as serious as the primary outbreak.

HSV spends most of its life-cycle in a nerve junction, called a ganglion, inside the body. During periods of activation (possibly associated with periods of decreased immune function by the “host”), the virus travels down the nerve to the original site of entry. But it rarely, if ever, will be found in the bloodstream of the host except during a primary outbreak.

A human host will produce antibodies against HSV. For a few, it is possible that these antibodies will kill the virus producing a cure. However, for most, the antibody response is not sufficient to kill off all the virus, and infection is lifelong. For those with a normal, healthy immune system, recurrent infections are infrequent and not too severe. For those with impaired immune systems the virus may infect other parts of the body.

A fetus or newborn may become infected by its mother. A fetus or newborn who develops a full body/blood infection can become very ill and possibly die. The mortality rate of disseminated herpes infection of the newborn is about 50%. And those babies who live often have severe problems afterwards. Fortunately, even though the percentage of the human population who are infected with HSV is very high, the risk of transmission to the fetus or newborn is incredibly low. It is VERY IMPORTANT to note that the most severe fetal/newborn infections occur when a mother has a primary outbreak during the pregnancy AND the baby is born prematurely (probably as a result of the herpes infection). Women who enter a pregnancy already infected, even if they have recurrent outbreaks during the pregnancy, RARELY transmit the virus to their baby.

There is a remarkable difference in fetal transmission rates between mothers with primary outbreaks and mothers with recurrent outbreaks. This is probably due to the fact the HSV is not present in the blood except during a primary outbreak. It is also related to the absence of HSV-antibody in women who have never been infected. The antibody in the blood of women with previous infection probably keeps the virus out of the mother’s bloodstream where it cannot infect the fetus.

During the last 20 years, the management of pregnant women with herpes has gone through several changes. A trial period lasting a decade during which c-section was used liberally to prevent transmission of the virus to the baby did nothing to reduce the risk. It is fairly clear that almost all of the very worst newborn infections occur in women with primary infections with virus in the bloodstream which is transmitted across the placenta. Rarely is a newborn infected by contact with a recurrent lesion during birth, although this clearly happens occasionally.

The current standard of practice is to perform a c-section IF any woman has a primary or recurrent lesion during labor which the baby is likely to contact during birth. However, if the lesion is felt to be significantly far away from the vaginal opening (and this would need to be determined by your doctor or midwife), covering the lesion with an occlusive bandage and acyclovir ointment may allow a women (especially one with a recurrent infection) to deliver vaginally. It is clearly not necessary to deliver a woman by c-section who is a known herpes carrier but does not have a current outbreak.

If you have herpes, make sure that you discuss all this with your doctor or midwife. Find out how they address the issue. Inform your doctor or midwife when you have an outbreak OR when you feel one coming on. If you have frequent outbreaks, your doctor or midwife may want to induce labor during a time when you are between outbreaks (called a “window”). It is also possible to use an antiviral medication close to the due date to help provide the window of time to allow a “herpes free” birth.