Vaccinated children rarely get chickenpox, and if infected they usually experience a mild form of the disease, although they may infect unprotected children. The vaccine is usually given to infants 12-18 months of age and children between 19 months and 12 years of age. Adverse effects due to vaccination are rather minor and include pain and redness or swelling at the injection site. Severe reactions are rare. Trimming the child's nails short may prevent serious scratching injuries and bacterial infection of the lesions.
Shingles causes a limited but very painful rash.
Immunodeficient patients and those on immunosupressive drugs have an increase risk for developing particularly severe shingles. Shingles looks like chickenpox but involves only a limited area on one side of the body, called a dermatome. The virus that causes Shingles is a dormant virus of chicken pox, that lodged in the nerves near the spinal cord. Individuals who have shingles rashes cannot transmit shingles to another person but may transmit chickenpox to a susceptible individual. It is recommended that persons who develop shingles have a complete physical exam to exclude the presence of any potentially life-threatening illness.