Both chickenpox and shingles are caused by the same "varicella" virus. Chickenpox is most common in young children, whereas shingles is most common in adults. Chickenpox is very contagious with most children in the United States experiencing chickenpox before they are school-aged. The disease is spread by close contact (sharing breathing space or direct touching contact) with infected discharge from the nose, throat or rash. A vaccine against chickenpox and shingles is now available. Shingles usually occurs in individuals over the age of 50. It is not as contagious as chickenpox but can cause severe discomfort due to the rash it causes. To prevent chickenpox infection to others, it is important to stay home until the last blister has crusted over (about 5 days).