Meningitis / Encephalitis

Neonatal Herpes Part 1 – Clinical Background

Published on 27 Aug 2020

After nine months of pregnancy a mother gives birth to her new baby with little fuss. The baby seems healthy and well at first, but after an uneventful first week of life, things take a turn for the worse. The baby becomes fussy, irritated, won’t eat and develops a fever. The worried parents rush to the hospital, where the medical team isolates the baby in an ICU. The doctors try every kind of medication but can not regulate his temperature. A few short days later, to the parents’ dismay, the baby sadly passes away. An autopsy is carried out to find out the cause of death. The culprit turns out to be one of the most common pathogens, herpes simplex virus 1 (HSV 1), the very same virus that causes cold sores.1

This is the face of neonatal herpes.

Most people relate herpes infection to low risk, highly manageable diseases. However there is a more serious side of herpes infection in infants. In this post, we will review the disease known as neonatal herpes, an uncommon but often deadly disease in infants.

HSV infections are caused by herpes simplex virus 1 (HSV 1) and herpes simplex virus 2 (HSV 2). In adults, HSV 1 and HSV 2 are commonly associated with oral herpes (cold sores) or genital herpes. Both of these diseases are easily diagnosed and managed simply with antiviral medications.

The primary mode of transmission of this disease is from the mother to the neonate during the birthing process. Pregnant women who are experiencing a primary infection of HSV in their third trimester have the highest risk of infecting their babies. Infants usually exhibit symptoms within the first three weeks of life.

The three clinical classifications of neonatal herpes are Disseminated, Central Nervous System (CNS) and Skin Eyes and Mouth (SEM). It should be noted that these categories should be considered more as a spectrum rather than discrete sets of symptoms, for example disseminated neonatal herpes can present with meningitis and skin lesions that are associated with herpetic CNS and skin infections.

Fortunately neonatal herpes is treatable provided that the disease is recognized and diagnosed in time, the typical treatment includes the antiviral drug – acyclovir.  The mortality of infants with untreated neonatal herpes can be as high as 85% for those with disseminated herpes and 50% for those with CNS herpes infection.2, 4 Additionally, the majority of those who survive without treatment develop long term severe neurological conditions.3 Studies have shown that Acyclovir can reduce the mortality of infants with neonatal herpes to 54% for disseminated herpes and 14% for CNS herpes.2

It is important to emphasize that while neonatal herpes is rare, it has potentially severe consequences, thus diagnosis and follow-up laboratory assessment play a crucial role in coordinating a treatment regimen. In the next part of this series, we will focus on laboratory assessment in combination with clinical assessment for diagnosis and disease monitoring.

1. Gant M (2018 July 19) Fox News. Parents whose newborn babies died from herpes warn about deadly virus, Retrieved from
2. Kimberlin (2004 Jan) Clin Microbiol Rev 17(1): 1–13. Neonatal Herpes Simplex Infection
3. Shah S, Aronson O, Zeinab M, Lorch S (Dec 2011) Pediatrics. Delayed Acyclovir Therapy and Death Among Neonates With Herpes Simplex Virus Infection
4. Tesini B (July 2018) Merck Manual. Neonatal Herpes Simplex Virus (HSV) Infection, Retrieved from

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