Neonatal Herpes Infections of Newborns

Female doctor examining newborn baby in incubator. Blend Images - ERproductions Ltd / Brand X Pictures / Getty Images

Neonatal herpes occurs when a baby is infected with either HSV-1 or HSV-2 near the time of birth. This type of infection is extremely dangerous. It can lead to lifelong disability or even death. Fortunately, neonatal herpes is relatively rare. Scientists estimate that there are only around 1500 cases of neonatal herpes a year in the United States. That works out to around one case for every 3200 deliveries.

There are three types of neonatal herpes:

  • Disseminated disease, which involves multiple organs This usually shows up around 10-12 days of life. It is the most dangerous kind of neonatal herpes. It can lead to numerous problems including
    • Sepsis
    • Respiratory failure
    • Liver failure
    • Disseminated intravascular coagulation, or DIC, where blood clots form throughout the baby's body
    Interesting Fact: Two-thirds of infants with disseminated neonatal herpes develop swelling in the brain. 40 percent never get a rash.
  • CNS, or central nervous system, disease. This represents about 1/3 of neonatal herpes cases. It usually shows up between 2-3 weeks of life. Most of these infants have skin lesions at some point, and symptoms include:
    • seizures
    • tiredness
    • irritability
    • trouble eating or decreased appetite
    • problems maintaining body temperature
    • swelling at the fontanelles (soft spots)
  • SEM disease, which is limited to the skin, eye, and/or mouth. Now that antivirals are available, this makes up about half of all cases of neonatal herpes. Even more of these infants get a rash than those with CNS disease. These infants also have symptoms by 10-12 days of life.

    Fortunately, effective herpes treatments are available. Acyclovir has been shown to be an effective treatment for neonatal herpes. However, the risks are still high. Even with treatment, up to 30% of infants with disseminated neonatal herpes still die before they reach their first birthday. Death is much rarer with treated forms of the other types of neonatal herpes.

    The mortality rate for CNS herpes is only 4 percent with treatment.

    Treatment may also reduce the risk of long-term disability. Studies have shown that treated infants with SEM disease have very few long-term problems. However, other forms of neonatal herpes, or SEM disease without effective treatment, can lead to a number of serious, lifelong problems for an infant. Some types of damage that can be caused by neonatal herpes infection include:

    • Intellectual disabilities
    • Paralysis of two or four limbs
    • Behavioral problems
    • Delayed speech
    • Learning disorders
    • Eye problems

    Babies Who Are at Greatest Risk for Neonatal Herpes

    Women who become infected with a genital herpes infection during pregnancy are generally considered to have the greatest risk of transmitting herpes to their baby. This is particularly true if they are genitally infected with HSV-1 rather than HSV-2. The other major factor considered to cause significant risk for neonatal herpes infections is the presence of a genital herpes outbreak at the time of birth. Women who have a genital outbreak when they go into labor may be counseled to consider a cesarean section instead of a vaginal birth. Other pregnancy-related risk factors for neonatal herpes include prolonged rupture of membranes before the infant is delivered and use of fetal scalp electrodes

    In addition, there are several ways that neonatal herpes can be transmitted after birth. For example, in 2015 scientists showed that Jewish ritual circumcision may also put infants at risk for neonatal herpes. This is because ritual circumcision can include direct oral suction of the wound. If the person performing the circumcision has an oral herpes infection, such direct contact can lead to herpes transmission. This type of transmission similar to how herpes transmission occurs during oral sex. This risk does not exist during medical circumcision procedures. Those procedures do NOT involve oral contact between the provider and the infant.

    However, medical circumcision can be controversial for other reasons.

    Another uncommon way that neonatal herpes transmission can occur is during breastfeeding. Herpes cannot be transmitted through breast milk. However, women can develop herpes lesions on their breasts. If a baby has oral contact with these lesions, it can cause neonatal herpes. Such transmission is quite rare. That said, there have been several case reports in the literature. Therefore, breastfeeding women with lesions on their breasts should talk with their doctor about any possible risk of a mammary herpes infection.

    How Do Doctors Reduce the Risk of Neonatal Herpes?

    There are several ways that doctors reduce the risk of neonatal herpes. These include:

    1. Encouraging the use of suppressive therapy by women who are either newly infected during pregnancy or who experience symptomatic outbreaks. This reduces the likelihood that a woman will experience an outbreak near the time of delivery. It also reduces the chance of asymptomatic shedding. The less virus in a woman's system, the lower the chances that her baby will be exposed.
    2. Recommending cesarean sections instead of vaginal delivery for women who have a genital herpes outbreak near their baby's due date. This reduces the chance that the baby will come into contact with any active sores in a woman's vagina or on the surface of her genitals. Such sores present the greatest risk of transmission of the herpes virus.
    3. Encouraging serodiscordant couples to practice safer sex during pregnancy. Doing this reduces the likelihood that a woman will become newly genitally infected with herpes during pregnancy. Since new infections are associated with the highest risk of transmission, that's an important goal. (This includes oral sex since transmission of herpes from the mouth to the genitals is an increasingly common cause of genital herpes.)


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    Leas BF, Umscheid CA. Neonatal Herpes Simplex Virus Type 1 Infection and Jewish Ritual Circumcision With Oral Suction: A Systematic Review. J Pediatric Infect Dis Soc. 2015 Jun;4(2):126-31. doi: 10.1093/jpids/piu075.

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