The chicken pox (varicella) vaccine

Sep 23, 2009 at 11:27 a.m. ET

Chickenpox, also known as varicella, is a virus that causes a high fever and characteristic itchy red rash that can range from a few spots to hundreds that cover the entire body. A vaccine is available to prevent the dreaded childhood disease.

Boy with chickenpox

Who gets chicken pox?

The chickenpox (varicella) vaccine is recommended for children 12 months and older. Those who are older and have had chickenpox in the past do not need to get the vaccine, although receiving it would not pose any major health concerns.

People who should not receive the vaccine include:

  • People with weak immune system;
  • Pregnant women or those who are trying to get pregnant;
  • People who have prior history of severe allegic reaction to the vaccine or components of the vaccine;
  • Children under the age of 12 months.

What are the symptoms?

The chickenpox virus, Varicella-zoster, causes symptoms that usually begin with a high fever followed by a red rash -- ranging from a few to hundreds of spots dotting the skin -- can be itchy. Some spots may become large, fluid-filled blisters. The spots typically dry within four to five days, and the whole healing process can take from seven to 10 days. The virus can be spread through physical contact or through the air via coughing and/or sneezing.

Vaccine recommendations

This vaccine is administered via needle injection that can cause temporary side effects. Most people feel tenderness in the area of the injection. Some may also have a mild fever that can last for a few days, and a few may experience a slight rash that resembles chickenpox within a week or two of the vaccination, but this should clear up within 5 days.

What you need to know

Doctors generally believe that you can get the chickenpox only once in your lifetime, because exposure creates immunity. It's possible, however, for the virus to remain dormant in the body and reactivate later on, causing a second bout of chickenpox.

Babies and people with very weak immune systems can experience serious complications should they get the disease, include bacterial skin infections, scars, pneumonia and encephalitis (inflammation of the brain), chickenpox also can cause birth defects.