What Is Neonatal Herpes?
Neonatal herpes infections are herpes infections that occur during pregnancy or within the first 28 days after birth. Unlike adult herpes infections, neonatal herpes has serious systemic consequences. The survival rate is only 40 percent, and it can also lead to serious disability.
How Do Infants Become Infected With Herpes?
Most neonatal herpes infections occur when an infant is exposed during delivery; however, it is possible for the fetus to become infected with herpes during pregnancy or after birth. The risk of neonatal herpes infection is highest when a woman becomes infected with herpes during her pregnancy. It is much lower when a woman has been infected with HSV long-term - even if her infection reactivates. Women who become infected with herpes during pregnancy have between a 25 and 50 percent chance of having an infant with neonatal herpes, compared to a less than one percent risk for women with pre-existing HSV-2 infections.
Neonatal herpes transmission can occur whether or not a woman has lesions, because women often experience asymptomatic shedding from the cervix or other genital skin. Some scientists believe that the reason neonatal herpes transmission rates are so much higher in women who become infected during pregnancy is because they do not have antibodies that can keep the virus from crossing the placenta, rather than because women with established infections are producing less virus or shedding less often.
How Common Is Neonatal Herpes?
Neonatal herpes is only reportable in a small minority of U.S. states, which makes it difficult to track. However, there are estimates that neonatal herpes transmission occurs in somewhere between 12 and 60 out of every 100,000 births in the United States.
This is a very low transmission rate when you consider that scientists estimate that approximately 30 to 65 percent of pregnant women have genital herpes infections caused by either HSV-1 or HSV-2.
How Is Neonatal Herpes Treated?
Neonatal herpes can either show up as an infection of the skin, eyes, and mucosal surfaces, or it can appear as a systemic infection involving the central nervous system. In either case, treatment involves intravenous infusions with high dose acyclovir. For infants with only superficial infection, treatment reduces the chance of complications as well as the chances of the infection becoming systemic.
When a neonatal herpes infection is systemic, children do not always have typical herpes lesions. Instead, they are more likely to be tired, lack hunger, and/or experience seizures. These cases are the ones at high risk of poor long-term developmental outcomes, even with early IV acyclovir treatment. In particular, disseminated herpes infections which affect multiple organ systems have the highest mortality rates.
In addition to early IV acyclovir treatment, children with neonatal herpes infections may require long-term suppressive therapy to reduce the frequency of skin outbreaks throughout their childhoods.
What Are the Complications of Neonatal Herpes?
Complications of neonatal herpes can include blindness, developmental delays, epilepsy, and cognitive disabilities as well as, in the most severe cases, death. These problems are somewhat more common for infant herpes infections that are caused by HSV-2 than for those caused by HSV-1. However, there is some evidence that there may be a substantially greater risk of neonatal herpes transmission from mothers with genital HSV-1 infection than from those infected with HSV-2.
Note: If you are a pregnant woman who has either been diagnosed with herpes, or whose partner has herpes, it is important to inform your doctor. That way she can perform appropriate testing on you, your infant, and potentially your partner to try and reduce the risk of an infant herpes infection. If your partner is infected with herpes, but you are not, it is also a very good idea to practice safe sex during pregnancy to reduce the risk of the new infections that are associated with a particularly high rate of neonatal herpes transmission.
Sources:
Brown EL, Gardella C, Malm G, Prober CG, Forsgren M, Krantz EM, Arvin AM, Yasukawa LL, Mohan K, Brown Z, Corey L, Wald A. Effect of maternal herpes simplex virus (HSV) serostatus and HSV type on risk of neonatal herpes. Acta Obstet Gynecol Scand. 2007;86(5):523-9.
Corey T, Wald A. Maternal and Neonatal HSV Infections N Engl J Med. 2009 October 1; 361(14): 1376–1385.
Dinh TH, Dunne EF, Markowitz LE, Weinstock H, Berman S. Assessing neonatal herpes reporting in the United States, 2000-2005. Sex Transm Dis. 2008 Jan;35(1):19-21.
Xu F, Markowitz LE, Gottlieb SL, Berman SM. Seroprevalence of herpes simplex virus types 1 and 2 in pregnant women in the United States. Am J Obstet Gynecol. 2007 Jan;196(1):43.e1-6.
