There are now new recommendations that a second dose of the varicella or chicken pox vaccine should be administered as a booster to the initial dose. The varicella vaccine was initially introduced to the routine pediatric immunization schedule in 1995 and has significantly decreased the burden of serious disease, hospitalization, school and work absence associated with the disease.
Routine surveillance has revealed that immunity levels after only one dose of the vaccine have waned leading to an increased exposure to the disease particularly in the school aged child. For this reason the American Academy of Pediatrics is now recommending a first dose of the vaccine at one year of age and a second dose of the vaccine at five years of age. This schedule applies to those who are currently initiating the vaccine series or have done so within the last four years. If a child older than five years has previously had a varicella vaccine, he should receive a second dose as well even though the interval between the doses is different than the new guidelines.
Some children who received the varicella vaccine have been exposed to the active disease and subsequently developed an outbreak of pox. In this case, it may not be necessary to receive the booster vaccination. This decision can be made by checking the child‘s immunity to varicella. This can be completed by performing a simple blood test of the patient’s antibodies to varicella. If the patient is found to be immune with a substantial IgG antibody there is not a reason to receive the booster dose. If there is not significant antibody the child should take the second dose of the vaccine.
Chickenpox can be particularly severe in adolescents and young adults. Close living circumstances seem to increase the rate of disease exposure and outbreak. It is important that any child or adult that has not had chickenpox, or alternatively received the vaccine, do so to avoid this level of disease and potential complications.
The two dose series applies to those who start at later than five years as well and may be administered three months apart to achieve comparable immunity. Again, if there is doubt that a family member has gained immunity to varicella his immunity should be evaluated by checking antibody levels.
Further information about varicella and the vaccine may be found through the American Academy of Pediatrics website, aap.org for a more in depth look at the history of the disease and the benefits achieved through vaccination for the individual and the community.