What is the incubation period of chicken pox?

Updated April 17, 2017

Chicken pox is a common contagious disease. It usually occurs in children less than 12 years of age, but can develop in people of any age. The symptoms of this illness are fever, headache, sore throat and a rash of red spots and blisters. The eMedTV website reports that prior to 1995 and the introduction of varicella vaccine, there were approximately 4 million cases of the illness annually. This number has dropped considerably with immunisation of school age children.

Spread of Chicken Pox

Chicken pox is transmitted through the air. When an individual with chicken pox coughs or sneezes, tiny droplets are expelled into the air. These carry the varicella-zoster virus. If someone who has never been infected with chicken pox inhales this virus, it enters her lungs and is carried through the blood to the skin, causing the rash associated with this disease. The virus also causes an initial respiratory infection.

Incubation Period

When a person inhales the virus, it takes between 10 and 21 days for her to develop the disease. This is the incubation period. While this represents the complete range, eMedTV reports that the average incubation period is 14 to 16 days. The first sign of the disease when the virus becomes active might not be the rash. In some people, swollen glands and flu-like symptoms are precursors to the red spots.

Incubation vs. Contagious

The incubation period should not be confused with how long an individual is contagious to other individuals. The contagious period of a person with varicella is one to two days before the rash develops. They remain contagious until all the blisters have formed scabs. This is because while scabs are not infectious, the blisters contain the virus. These blisters usually take about five to six days from the start of the rash to crust over.


Chicken pox is a preventable disease. The best way to avoid this illness is to get vaccinated. Vaccinated individuals still may contract varicella, but if so it is usually milder than those who have not been vaccinated. If you know you have been exposed to the virus you should avoid anyone with a compromised immune system. Also avoid pregnant women as fetal abnormalities can be caused by chicken pox. Avoid these people for the full range of the incubation period (21 days). If you develop the disease, stay home until you are no longer contagious.

Other Preventive Measures

The chicken pox virus can be spread when it lands on objects after a cough or sneeze by an infected individual. Some of these objects include toys, clothes, furniture and bedding. If someone in a house has chicken pox, wipe down surfaces with a sterilising compound. Wash clothes and bedding thoroughly and often. Follow preventive measures throughout the course of exposure (if known), the incubation period (21 days or until disease develops), disease development and blister scabbing.

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About the Author

Ellen Topness has been a counselor in the mental health field for more than 25 years. She has a Master of Arts in counseling. Throughout her career, Topness has enjoyed writing articles, poems and vignettes for pleasure. She also released a new ebook, "A Natural Disaster: Learning to Survive Myself."