Nine-tenths of the population have had chickenpox by the age of 15 years. It usually occurs in childhood. Nine-tenths of cases occur in boys and girls less than 10 years old. It is highly contagious, being spread through the air by coughing and sneezing. It is contagious from 2 days before the rash appears until all the spots have crusted over.
Second attacks are rare.
In healthy children, complications are unusual. The virus which causes shingles and chickenpox . Essential Facts Also caused by the varicella zoster virus.