Passing through the birth canal (birth-acquired herpes, the most common method of infection)
Right after birth (postpartum) from kissing or having other contact with someone who has herpes mouth sores
If the mother has an active genital herpes infection at the time of delivery, the baby is more likely to become infected during birth. Some mothers may not be aware they have internal (inside the vagina) herpes sores.
Some people have had herpes infections in the past, but were not aware of it. These people, not knowing that they have herpes, may pass it to their baby.
Herpes type 2 (genital herpes) is the most common cause of herpes infection in newborn babies, but herpes type 1 (oral herpes) can also occur.
Herpes may only appear as a skin infection. Small, fluid-filled blisters (vesicles) may appear. These blisters rupture, crust over, and finally heal, often leaving a mild scar.
Herpes infection may also spread throughout the body (called disseminated herpes). In this type, the herpes virus can affect many different parts of the body.
Herpes infection in the brain is called herpes encephalitis
The liver, lungs, and kidneys may also be involved
There may or may not be blisters on the skin
Newborn infants with herpes that has spread to the brain or other parts of the body are often very sick. Symptoms include:
Herpes virus infections in infants are generally treated with medicine given through a vein (intravenous). Acyclovir is the most common antiviral medicine used for this purpose. The baby may need to take the medicine for several weeks.
Other therapy is often needed to treat the effects of herpes infection, such as shock or seizures. Often, because these babies are very ill, treatment is done in an intensive care unit.
Infants with systemic herpes or encephalitis often do poorly, despite antiviral medications and early treatment.
In infants with skin disease, the vesicles may come back repeatedly even after treatment is finished. These recurrences put them at risk for learning disabilities, and may need to be treated.
If your baby has any symptoms of birth-acquired herpes, including skin lesions alone, have the baby seen by your health care provider promptly.
It is important for women to tell their doctor if they have a history of genital herpes.
Safer sexual practices can help prevent the mother from getting genital herpes. Mothers who are not infected with herpes cannot pass the herpes virus to the baby during delivery.
People with "cold sores" (herpes labialis) should avoid contact with newborn infants. Caregivers who have a cold sore should wear a surgical mask and wash their hands carefully before coming into contact with the infant to prevent transmitting the virus.
Mothers should speak to their health care providers about the best way to minimize the risk of transmitting herpes to their infant.
Red Book: 2009 Report on The Committee on Infectious Diseases, American Academy of Pediatrics.
Cernik C, Gallina K, Brodell RT. The treatment of herpes simplex infections: An evidence-based review. Arch Intern Med. 2008;168(11):1137-1144.
Hollier LM, Wendel GD. Third trimester antiviral prophylaxis for preventing maternal genital herpes simplex virus (HSV) recurrences and neonatal infection. Cochrane Database Syst Rev. 2008;23(1):CD004946.
Sameer Patel, MD, Assistant Professor of Pediatrics, Columbia University, New York, NY. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.