• pregnant women 
• newborns 
• teens 
• adults, and 
• people who have immune system problems that make it hard for the body to fight infection.

• A fever and feeling tired before a rash develops
• Small, red, flat spots that usually first appear on stomach, back, face, and scalp and then spread to the rest of the body
• The spots develop into fluid-filled blisters which are usually less than a quarter inch wide and have a red base
  
• After the blisters break, the open sores will become covered by dry, brown scabs

Chickenpox is caused by a virus called varicella-zoster virus.  

Chickenpox is spread by:

• Close physical contact with an infected person.  In a household, chickenpox will spread to most of the household members who have not had the disease or received chickenpox vaccine
• Breathing in the droplets in the air when an infected person coughs or sneezes 
• Touching the fluid from a chickenpox blister
• A pregnant woman with chickenpox can pass it on to her baby during pregnancy 
• A mother with chickenpox can pass it on to her newborn

Complications may include:

• Skin infections, including necrotizing fasciitis (flesh eating disease)
• pneumonia and
• central nervous system problems. 

A person is contagious from about 2 days before spots appear and until all blisters have crusted over, which is usually 5 days after the first blisters appear.
 
People who are contagious should stay away from child care, school, or work to avoid spreading chickenpox to others.

After you have had chickenpox, you are not likely to get it again.  However, the virus stays in your body long after you get over the illness. If the virus becomes active again, it can cause a painful rash called shingles or zoster.