We are currently seeing cases of chickenpox, a viral illness that is caused by a very contagious virus, varicella zoster. To contract chickenpox, a child usually is exposed to another child with it. Then, in about 2 weeks, the child develops a mild fever and an itchy, bumpy red rash. The red bumps turn into very small blisters. The blisters eventually crust over and scab, and then heal back to normal skin. There is a very effective vaccine to prevent your child from getting chickenpox, and most children who have not had chickenpox should receive the vaccine at any time after their first birthday.