Chickenpox is a contagious illness caused by the varicella-zoster virus. Once an almost standard part of childhood, outbreaks of this condition have become less common throughout all age groups since the introduction of the chickenpox vaccine in 1995.

Babies can’t receive the vaccine until they’re at least 12 months old. However, cases of chickenpox in babies under 1 year still went down by 90 percent between 1995 and 2008, the Centers for Disease Control and Prevention reports. This may be due, in part, to “herd immunity.”

Herd immunity, also called community immunity, indirectly helps protect those who can’t be immunized, like babies, from getting a disease. When a large amount of a population is vaccinated, the chance of an outbreak is low. So with the introduction of the chickenpox vaccine, once most children were immunized, young infants weren’t exposed to chickenpox nearly as often as in the pre-vaccine era.

Babies can contract chickenpox if they’re exposed to it, but they may have a milder case if they have passive immunity. Passive immunity is when the mother passes her own immunity onto her baby during the last trimester of pregnancy and while breastfeeding.

Babies can also get chickenpox from their mother if she contracts it during or after pregnancy. Since passive immunity isn’t present right away, a baby who contracts chickenpox from their mother right around birth may become severely ill.

Babies may also contract chickenpox from someone with shingles if they come into direct contact with the fluid that oozes out of the rash blisters. The same virus that causes chickenpox causes shingles.

Read on to learn more about the signs of chickenpox in babies and how to treat and protect your child.

What are the symptoms of chickenpox in babies?

The first signs of chickenpox in babies may include:

  • fever, or a temperature of around 101°F to 102°F (38.3°C to 38.9°C)
  • poor feeding
  • coughing
  • fussiness
  • fatigue
  • sleeping more than usual

These symptoms may start a day or two before the chickenpox rash starts to appear. The red, very itchy rash often starts to show on the torso, stomach, scalp, or face. An all-over rash then follows. The rash may be mild or severe. It occurs in successive waves over two to four days. As many as 200 to 500 itchy bumps eventually erupt all over the body.

The chickenpox rash has several stages. It starts out as tiny red bumps. Over the course of several days, the bumps become fluid-filled blisters. When the blisters break, they leak and resemble open sores. The blisters then start to scab over and heal. Chickenpox may last anywhere from 5 to 10 days. Since the rash comes on in waves, it’s common to see bumps, blisters, open sores, and scabs all at the same time.

Picture of chickenpox rash

What’s the incubation period for chickenpox?

Chickenpox is very contagious. It’s spread through direct contact with the blisters, saliva, or mucus of a person with the infection. It can also spread through the air if someone with the infection coughs or sneezes.

Symptoms of chickenpox can start to occur anywhere from 10 to 21 days after exposure.

How long are you contagious?

A person becomes contagious approximately two days before the rash starts to show. They’ll remain contagious until every blister becomes scabbed over and dry. This may take about five days or longer. That means you should expect to keep your baby home from child care facilities or other areas with children for about 7 to 10 days, starting with the onset of their fever.

Does your baby need to see a doctor?

If you suspect your baby has chickenpox, you should contact their pediatrician, even if their rash and symptoms are mild.

Make sure to let your child’s doctor know if your baby has any of the following symptoms. They might indicate complications:

  • a fever of 102°F (38.9°C) or higher
  • rash in one or both eyes
  • a rash that feels warm to the touch
  • extreme drowsiness or inability to wake up
  • stiff neck
  • severe cough
  • vomiting
  • fast heartbeat
  • trouble breathing
  • muscle tremors

How is chickenpox in babies treated?

Since a virus causes chickenpox, it’s not treated with antibiotics. If, however, a bacterial infection occurs around the blisters, your baby’s doctor may prescribe them antibiotics to help clear it up. Scratching or rubbing can lead to an infection of this type.

You can prevent a bacterial infection from developing by keeping mittens on your baby’s hands and keeping their nails clipped. Also make sure not to rub their skin after bathing. Pat it dry instead, which can reduce irritation to the rash.

If your baby is at risk for complications, their doctor may prescribe an antiviral medication. This may be needed if they were born prematurely or if they have a compromised immune system.

Other treatments for chickenpox are geared toward keeping your baby comfortable, the same way you would an older child:

  • Help reduce itching with calamine lotion and oatmeal baths.
  • Let your baby get plenty of rest.
  • Keep your baby hydrated.

WarningIf your baby is under 3 months old, don’t give them any type of fever-reducing medication without checking with their doctor first. Never give a baby aspirin. It could lead to a rare yet serious condition called Reye’s syndrome.

What are the possible complications?

Chickenpox often goes away on its own without any complications. Whether it’s mild or severe, most people become immune to chickenpox after getting the disease or after receiving even one dose of the vaccine. However, if you have a compromised immune system, you may get chickenpox again.

If a pregnant woman has chickenpox, it can lead to severe complications for her baby. Chickenpox contracted early in pregnancy may result in limb deformities or low birth weight. Chickenpox contracted shortly before or after giving birth can cause a serious, life-threatening infection.

Babies born without passive immunity to chickenpox may also be at higher risk for complications. These include:

Tips for prevention

The chickenpox vaccine is around 94 percent effective after both doses, according to Vaccines.gov. Babies under 1 year can’t get the vaccine. It’s given to toddlers starting at 12 months of age. Children then need a booster shot between ages 4 and 6 to improve their immunity to the virus. This is because the effectiveness of the first vaccine dose decreases some after five years. A baby or toddler who hasn’t received the vaccination should be kept away from a person with chickenpox or shingles.

Herd immunity can also play a factor in protecting your baby from chickenpox. But if you live in a community where vaccinations are less common, keep your young infant away from children as much as possible.

What’s the outlook?

The chickenpox vaccine has reduced outbreaks significantly. Babies may, however, still contract the virus. If you suspect that your baby has chickenpox, make sure to call their doctor immediately. Chickenpox is usually mild, but can result in complications.