Neonatal Herpes

What is neonatal herpes?

Neonatal herpes is a type of herpes infection that develops in a baby during their first six weeks of life. It typically occurs when the herpes simplex virus (HSV) passes from a pregnant person to their baby, most commonly during delivery.

Neonatal herpes is very different from herpes in older kids and adults. It doesn’t simply mean your baby has cold sores on their face. In newborns, HSV is dangerous and potentially life-threatening. It can cause a widespread infection that affects your baby’s major organs, including their brain. Prompt treatment gives your baby the best chance at a good outcome.

In the U.S., neonatal herpes affects anywhere from 5 to 33 per 100,000 live births. This means each year, about 1,500 babies are born with neonatal herpes. Some research shows this number has been going up in recent years. It’s not yet clear why.

Types of this condition

There are three main types of neonatal herpes. Healthcare providers classify the condition according to the parts of a baby’s body that HSV affects:

• Skin, eye and mouth disease (SEM disease). Fluid-filled blisters form on your baby’s skin, in their mouth and around their eyes.
• CNS disease (brain disease). The virus grows and multiplies in your baby’s central nervous system, affecting their brain and spinal cord. Your baby may not have signs or symptoms early on, and blisters may not form on their skin.
• Disseminated disease: The virus affects multiple parts of your baby’s body, including major organs like their liver and lungs. In some cases, it affects your baby’s brain.

What are the signs your baby has herpes?

Fluid-filled blisters affecting your baby’s skin, eye area and mouth are the most obvious sign. But not all babies with neonatal herpes develop these blisters. It depends on the type of neonatal herpes they have.

Signs and symptoms can appear any time within the first six weeks of life, but they almost always develop within the first four weeks. You can notice some things at home like the blisters or your baby not taking feeds, having breathing difficulty and not acting right. In this case, you should contact your provider immediately. But other things are only detected at a medical appointment.

Call 911 or your local emergency services number if your baby has trouble breathing or you can’t wake them up.

Signs and symptoms of skin, eye and mouth disease (SEM disease)

These usually appear between nine to 11 days after birth and include:

• Clear, fluid-filled blisters on your baby’s skin. The surrounding skin may look discolored. The blisters may touch each other or form clusters.
• Fluid-filled blisters on your baby’s eyelids or around their eyes. Your baby’s eyes may look red or very watery, and their eyelids may be swollen. 
• Sores in your baby’s mouth, including on their tongue and the roof of their mouth.

Signs and symptoms of brain disease

These usually appear 16 to 19 days after birth and include:

• Extreme sleepiness.
• Irritability.
• Shaking.
• Little or no interest in feeding.
• Unstable body temperature (too high or low).
• Bulging soft spots on their scalp.
• Seizures.
• Fluid-filled blisters on their skin. These appear in 60% to 70% of newborns with brain disease.

Signs and symptoms of disseminated disease

These usually appear 10 to 12 days after birth. Things you may notice in your baby include:

• Unstable body temperature (too high or low).
• Irritability.
• Extreme sleepiness.
• Little or no interest in feeding.
• Fast breathing and other changes to their breathing pattern (respiratory distress).
• Swollen belly.
• Fluid-filled blisters on their skin. These appear in about 60% of babies with disseminated disease, often later in the course of the infection.

Signs a provider may find through testing include:

• Problems with blood clotting (disseminated intravascular coagulation).
• Liver failure.
• Brain swelling (encephalitis).
• Heart muscle inflammation (myocarditis).

What causes neonatal herpes?

The herpes simplex virus (HSV) causes neonatal herpes. Newborns can get very sick from HSV because their immune systems are still developing.

How is neonatal herpes transmitted?

Most often (85% of cases), the virus spreads from a pregnant person to their baby during their delivery. This can happen if the virus is present in the genital tract as the baby passes through.

Although it’s less common (10% of cases), newborns can get the infection from exposure to the virus after delivery. For example, this can happen if someone who has a cold sore gives your baby a kiss. It can also happen if someone who has a herpes skin infection (herpetic whitlow) touches your baby.

The least common way (5% of cases) is for the virus to reach the fetus at some point during pregnancy. Providers call this intrauterine infection. It means HSV travels to the fetus through the placenta. The typical signs and symptoms of neonatal herpes appear within 48 hours of birth. In some cases, intrauterine infection leads to miscarriage.

Risk factors for transmission during delivery

HSV can only spread during delivery if you have an active genital herpes infection at that time. It’s important to know that you can have an active infection even without symptoms. All it takes is for the virus to be present in your genital tract (including your vulva, vagina or cervix). The virus can be there without you noticing any symptoms. 

Research shows the risk can vary widely depending on when you first get the herpes infection:

• During pregnancy (with no prior herpes exposure). The risk of passing herpes to your baby is the highest if you first get infected with genital herpes during pregnancy, particularly during the second half as you get closer to your due date. Healthcare providers call this a primary first episode. It’s when either HSV subtype (HSV-1 or HSV-2) causes a genital herpes infection and you have no prior exposure to the other subtype. This means HSV is in your body for the first time, and you have no antibodies against either type. A primary first episode later in pregnancy makes it much more likely that the virus will be present in your genital tract during delivery.
• During pregnancy (with prior exposure to the other HSV subtype). This is when you get genital herpes from one specific subtype for the first time during pregnancy. But you have antibodies against the other subtype from prior exposure. Research shows there’s still a substantial risk of passing the virus to your baby, but it’s likely lower than if you had no prior exposure to HSV. This is because your preexisting antibodies pass to your baby through the placenta, offering them some protection.
• Before pregnancy. If you get genital herpes before becoming pregnant, the risk of passing the virus to your baby is low. The virus would need to reactivate during delivery (recurrent infection) in order to spread to your baby. Even if HSV does reactivate, research shows that a recurrent infection is much less likely to cause neonatal herpes compared to an infection that occurs for the first time during pregnancy. This is because antibodies from your past infection pass to your baby and help protect them.

What makes neonatal herpes a very serious condition?

Neonatal herpes is a serious condition because it can harm your baby’s organs, including their brain. For example, it can lead to swelling of their brain (herpetic encephalitis). Neonatal herpes can also be fatal, even with treatment.

Skin, eye and mouth (SEM) disease doesn’t initially affect your baby’s brain or other internal organs. But the disease is still serious because it can lead to permanent eye damage and vision loss. Also, without treatment, SEM disease can progress to brain disease or disseminated disease.

How is neonatal herpes diagnosed?

Healthcare providers diagnose neonatal herpes by reviewing your baby’s signs and symptoms and doing testing. They need to rule out other conditions that may cause similar things. For example, a common (and harmless) condition called erythema toxicum neonatorum causes a rash and fluid-filled bumps.

If providers suspect herpes, they do testing right away to check for the presence of the herpes simplex virus in your baby’s body.

What tests will my baby need?

A provider will collect fluid samples from your baby’s body. This involves using a swab to gently take samples from your baby’s:

• Mouth.
• Eyes.
• Throat (the top part, called their nasopharynx).
• Anus (butthole).
• Blisters, if they’re present.

Your baby’s provider may also collect samples of:

• Blood.
• Cerebrospinal fluid (CSF), which is fluid collected from your baby’s spine. This requires a lumbar puncture.

Lab testing

Your baby’s provider will send the samples to a lab for testing. Possible tests include:

• Viral culture test. This uses specific techniques to encourage HSV in a fluid sample to grow. If there’s no sign of growth after five days, providers usually consider the test negative (no HSV present).
• PCR (polymerase chain reaction) test. This looks for herpes simplex virus DNA in body fluid. Providers often use cerebrospinal fluid samples for this type of testing to see if the virus is affecting your baby’s central nervous system.

Other types of tests

If lab testing confirms your baby has herpes, then their care team will likely do:

• A chest X-ray.
• An abdominal X-ray.
• Brain imaging, like a brain MRI scan (magnetic resonance imaging scan).
• A detailed eye exam.

All these things help providers learn more about how the virus is affecting different parts of your baby’s body. They use this information to guide your baby’s treatment plan.

What is the treatment for neonatal herpes?

If healthcare providers suspect your baby has neonatal herpes, it’s very likely that your baby will be admitted to the hospital for treatment.

Providers use an antiviral medication called acyclovir to treat neonatal herpes. Your baby will receive this treatment through an IV and then by mouth (as a liquid). Here’s what you can expect:

• If your baby has skin, eye and mouth (SEM) disease, they’ll need IV treatment for 14 days. Then, they’ll complete a six-month course of oral medication. This lowers the risk of the skin blisters returning.
• If your baby has central nervous system (CNS) or disseminated disease, they’ll need IV treatment for 21 days. After completing IV treatment, your baby will need to take oral medications for six months. This supports your baby’s neurologic development and lowers the risk of long-term effects on their brain.

It’s important to know that some babies with CNS involvement need IV treatment for longer than 21 days. CNS involvement means a spinal tap showed the presence of HSV in your baby’s cerebrospinal fluid. This can happen with CNS disease or disseminated disease.

If this is the case, then your baby will need a follow-up spinal tap (examination of fluid from their spine) to make sure the virus is gone from their brain. The test must come back negative in order to stop IV treatment. Some babies need an extra week or longer to clear the virus from their brain. Only then can they start oral treatment.

How can you prevent neonatal herpes?

Healthcare providers do everything possible to prevent neonatal herpes. Here’s what to know:

• Antiviral medications may help. If you have a history of genital herpes, your provider may prescribe antiviral medication for you to take during the last several weeks of pregnancy. This reduces the risk of recurrence at the time of delivery and allows for a lower-risk vaginal birth.
• A C-section may be a safer option. Providers sometimes recommend a C-section if the benefits outweigh the risks. For example, they’ll likely do a C-section if you have an active infection at the time of delivery. In this case, there’s a high risk of your baby getting the infection during a vaginal delivery. So, a C-section is safer.
• Providers make adjustments during delivery. If you have a vaginal delivery, your provider can adjust which devices they use on your baby. For example, they may not use a fetal scalp monitor, which makes tiny breaks in your baby’s skin. When there’s a break in your baby’s skin, it’s easier for HSV to enter and cause an infection. Providers choose which devices to use or avoid according to your baby’s risk for infection.
• You and your provider are a team. It’s not always easy to talk about sex with a healthcare provider. It might feel uncomfortable or even intrusive. But talking with your provider about ways to prevent genital herpes can help keep you and your baby safe. For example, your provider may advise you to limit or avoid sexual activity during the last trimester if there’s a risk you could get a new herpes infection. Exposure to either HSV-1 or HSV-2 for the first time late in pregnancy is the leading risk factor for neonatal herpes.

What is the outlook for herpes in babies?

Your baby’s outlook depends on many factors, including the type of neonatal herpes they have and how well treatment controls the virus. Your baby’s care team can give you the most accurate sense of what to expect in the near and far future. Many babies with neonatal herpes recover. But in some cases, this condition is fatal.

Thanks to antivirals, more babies survive today than in the past. Today, 71% of babies with disseminated disease and 96% of babies with CNS disease survive at least to their first birthday.

Neonatal herpes sometimes leads to long-term effects. These include:

• Developmental delay (delay in achieving milestones at the expected time).
• Intellectual disability.
• Cerebral palsy (weakness in movements).
• Epilepsy.

The good news is that early intervention (activities and services tailored to each child’s needs) and continued support can help your child. For example, your child may benefit from physical therapy, speech therapy and assistive technologies (like screen readers).

When should I contact a healthcare provider?

If your baby has any signs of neonatal herpes, contact a healthcare provider right away. Neonatal herpes needs quick treatment. The sooner your baby gets treatment, the better their chances of survival — and of recovery with minimal or no long-term effects. Don’t wait until your baby’s next well-check.

Can babies get cold sores?

Yes. It’s possible for babies to get cold sores if they’re exposed to the herpes simplex virus (HSV). This virus can make newborns very sick. Contact a healthcare provider if you believe your baby was exposed or you notice symptoms.

Can you have a baby with herpes?

Absolutely. People with a history of genital herpes can and do give birth to healthy babies all the time. In fact, if you have a genital herpes diagnosis, the odds are good that you can have a baby without the virus causing any issues. This is because recurrent herpes infections are less likely to cause neonatal herpes compared to a first-time infection.

Still, it’s important to talk to your healthcare provider about your medical history so they can take any necessary precautions during pregnancy and delivery.

A note from Cleveland Clinic

You were prepared for a lot of things, but not this. A neonatal herpes diagnosis might come as a shock, especially if you didn’t even realize it was a possibility. Take one day at a time. Even one hour at a time.

Many babies respond well to treatment. Medical science has come a long way over the years, and there’s plenty of reason for hope.

If you’re feeling scared or overwhelmed, lean on your baby’s care team for support. They’ll help you understand next steps in treatment and what you can expect with each passing day.