Chickenpox | The Children's Hospital of Philadelphia

Parents PACK

Chickenpox (Varicella)

General information

Please visit the Vaccine Education Center for general information about chickenpox and the vaccine.

Additional information from past issues of the Parents PACK newsletter

Chickenpox catch-up

Q. My 3-year-old daughter never received the first dose of the chickenpox vaccine because the country we lived in when she was an infant did not offer it. Soon we are planning to move back to that country, is it necessary for her to get the chickenpox vaccine before we go?

A. The current recommendation in the U.S. for children who did not receive their first dose of chickenpox vaccine by 15 months is to get it as soon as is feasible, and then receive the second dose at 4-6 years of age. However, because you mention that you plan to leave the U.S. soon, it is possible for her to get the second dose of the chickenpox vaccine 3 months after getting the first dose.

If the chickenpox vaccine isn’t used in the country to which you are returning, there is likely to be a higher rate of disease than you see in the U.S. So, getting your daughter vaccinated before you move back will help protect her from getting chickenpox.

Read more about chickenpox and the chickenpox vaccine»


Spread of chickenpox

Chickenpox is very contagious. It can spread in one of three ways: by coughing or sneezing, physical contact with broken blisters, or by virus particles from the blisters that are sprayed in the air. Most unvaccinated people living in a house with someone who has chickenpox will also become ill. When one person gets chickenpox in a family of five in which no one is protected, at least three of the other family members will get chickenpox.


Natural immunity

Q. I would rather my child develop natural immunity to chickenpox, so that he is at less risk of developing chickenpox as an adult.

A. The good news is that regardless of whether we become immune to chickenpox from getting a vaccine or having the disease, our immune memory will protect us as adults. While there used to be a concern that the chickenpox vaccine would not provide lifelong immunity, data has not supported this concern. Immunity lasts at least 20 years and based on experience with the rubella vaccine, which is made the same way, is expected to be lifelong. Because the chickenpox vaccine affords immunity without the possibility of complications typically associated with natural infection, the vaccine offers immunity without the risk of disease.

As an aside, adults who have not had chickenpox disease or the vaccine should get vaccinated, since chickenpox disease in adults is often more severe.

Learn more about chickenpox and the vaccine.


Chickenpox: The disease, the vaccine and the parties

A mom sits in the waiting room of a pediatrician's office holding her 12-month-old child nervously on her lap, waiting for the child's name to be called . . . called to get his shots — one of which is a shot to protect him against chickenpox. She wonders if she is doing the right thing by having her child immunized.

At the same time, another mom sits casually conversing at a kitchen table with some women that she met about an hour ago. Her child is in another room having snacks and playing with a group of other children. Occasionally, she goes into the room to shift the sippy cups amongst the children. Later, she goes home and anxiously wonders if today's "play date" was successful — successful in exposing her child to chickenpox.

Elsewhere a mom sleeps in a chair next to her child's hospital bed. When she awakens, she looks at her child hooked up to tubes and beeping machines. She wonders when this nightmare will end. All she wanted to do was avoid that vaccine. Others had done it, and their children were fine. Why wasn't hers? Chickenpox wasn't that bad after all--was it?

As shown in the opening vignettes, all parents wonder whether they are making the best decisions for their children. The difference is the source of their angst the first mom wondered if she should immunize her child, the second, whether exposing her child to chickenpox worked, and the third when, and if, her child would recover. 

Historically, chickenpox has not been viewed as a dangerous disease, but rather a rite of passage. So when a vaccine became available in 1995, many parents, and even some doctors, didn't feel that it was necessary. As more states required the vaccine for children to go to school, parents desperate to avoid "yet another vaccine" started to seek out the disease for their children, intentionally exposing them to chickenpox.

A few years ago an article printed in the New York Post ("Inside New York Chicken Pox Parties" by Kate Torgovnick, January 11, 2009) described these so-called "chickenpox parties" highlighting the extremes that some parents are willing to go to in order to expose their children to the chickenpox virus. Parents interviewed for the story described encouraging their children to share lollipops, cups and clothing. 

The story went on to tell of one parent who posted an ad on Craigslist looking for anyone with the disease. It also told of parents going to the homes of complete strangers to intentionally expose their children to the virus. Unfortunately, in some cases, this decision may lead to serious illness and even death.

While it is scary to consider that a vaccine given to your child may cause harm, it is not likely to compare to the guilt and pain of a bad outcome from the disease. It is also a theoretical concern as compared to the very real possibility of getting the disease. Here are some facts to consider:

The disease

Typically, children with chickenpox experience an itchy rash of 250 to 500 blisters beginning on the chest and face and spreading over the entire body. They may be tired, feverish, and have a headache. Some children may experience vomiting or diarrhea. The illness usually lasts about five to 10 days.

Of 1,000 people with chickenpox:

Before the vaccine about 50 children died each year from chickenpox infection or its complications; many of these were previously healthy children.

The vaccine

Of 1,000 children who get the vaccine:

People who are allergic to gelatin should not get the vaccine.

In conclusion

Parents are confronted with many decisions, and at the end of the day, they must be willing to be okay with the outcome of those decisions - whatever that may be. Here's hoping you'll choose birthday parties, not chickenpox parties.


Chickenpox and the vaccine

Children between 4 and 6 years of age are recommended to get a second dose of the vaccine against chickenpox. The main reason for this is that 15 to 20 children out of every 100 were not protected against chickenpox after getting one dose of the vaccine. Getting a second dose enables more children to be protected as adults when chickenpox infections are more severe.

Adults with chickenpox often have a higher fever, longer illness, and a worse rash than children. They are seven times more likely to suffer from encephalitis (infection of the brain). And if a woman becomes infected with chickenpox during her first trimester of pregnancy, her unborn child may be harmed or miscarried. Birth defects caused by chickenpox during pregnancy may include shortened limbs, brain damage, cataracts, blindness or mental retardation. If the mother is infected late in her pregnancy, the baby may have a silent chickenpox infection that reawakens as shingles very early in life. A woman considering becoming pregnant who has not had chickenpox should consider getting vaccinated. Older children and adults who have not had chickenpox or the chickenpox vaccine - and those who have had only one dose - should also get the vaccine.

Chickenpox causes a rash on the chest, abdomen, scalp and face. The rash looks like blisters and is very itchy. Otherwise healthy children will usually get between 250 and 500 blisters. One of the most common complications of chickenpox occurs if a blister becomes infected with bacteria such as streptococci, the so-called "flesh-eating bacteria," that cause destruction of the muscles.

Unlike many vaccine-preventable diseases, chickenpox is one that most parents know about. Because the vaccine was only licensed in 1995, many young parents had chickenpox as children. Indeed, before the vaccine, about 4 million people got chickenpox every year. Of these, about 13,500 people were hospitalized and 150 died each year from chickenpox. Since the vaccine has been available, these numbers have declined about 10-fold. However, we still experience outbreaks of chickenpox every year. In late 2004, an outbreak in a school in Nebraska showed that students who were not vaccinated were more likely to get chickenpox, were more ill, and missed more days of school than children who were vaccinated.

The chickenpox vaccine is recommended for all children between 12 and 15 months of age and again between 4- and 6-years of age. The vaccine is also recommended for adolescents and adults who have not had chickenpox. One dose of the vaccine is given to children less than 13 years old and two doses - separated by at least one month - are recommended for people 13 years or older.


Allergies and the chickenpox vaccine

Because the chickenpox vaccine contains gelatin, people who are allergic to gelatin cannot get the vaccine. Gelatin is also contained in foods, like Jell-o, so a child's allergy may already be known before it is time to get the vaccine.


Chickenpox vaccine for adults

Q. I am 40 years old and recently got my chickenpox vaccine. I ended up with a fever and a rash as a result. Now I am wondering if I should get the second dose of the vaccine.

A. About 4 of every 100 adults who get the vaccine will develop a rash, usually with less than 10 blisters. You should still get your second dose of vaccine in one to two months as recommended. Your reaction to the first dose indicates that your body has made an immune response to the vaccine, so you are less likely to have the same thing happen after the second dose. However, the second dose will strengthen your immunity, so that if you are exposed to the chickenpox virus, you will be better protected.


Need for chickenpox vaccine after disease

Q. My daughter had chickenpox at 10 months old, but now that she is one, her doctor said she should still get the chickenpox vaccine. Is this really necessary?

A. The Centers for Disease Control and Prevention (CDC) recommends vaccination of all children at 12 months of age who do not have evidence of immunity. Evidence can include:

Because many rashes are misclassified, the CDC states that “if there is any doubt that the illness was actually varicella [chickenpox], the child should be vaccinated.”

While you could get your daughter tested for evidence of antibodies to chickenpox, the test will require a blood draw and if it is negative, she will still need to get the vaccine. Further, a dose of vaccine even if she has had chickenpox will not hurt her; it will make her immunity stronger. 


Updated: January 2013

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