A child received only one dose of varicella vaccine and subsequently tests positive for varicella IgG antibody. Does the child still need a second dose of varicella vaccine?

Varicella postvaccination serologic testing is not recommended; however, if a person tests positive for varicella antibody 28 days or more after vaccination, the Advisory Committee on Immunization Practices (ACIP) considers the person to be immune. Studies have shown that a second dose boosts antibody titers and indicators of cell-mediated immunity significantly above the levels produced by a single dose. A second dose may be required to comply with school entry or institutional immunization requirements, regardless of serologic test results. You can access the ACIP varicella vaccine recommendations, which include evidence of immunity (page 16) at www.cdc.gov/mmwr/pdf/rr/rr5604.pdf.