Single-antigen varicella vaccine also is recommended for All people ≥ 13 years who do not have evidence of immunity to varicella Evidence of immunity consists of one of the following: Documentation of 2 doses of varicella vaccine given ≥ 4 weeks apart History of varicella or herpes zoster verified by a health care practitioner Laboratory confirmation of protective levels of varicella antibodies Birth in the US before 1980, except for health care workers and pregnant women The varicella vaccine is recommended particularly for people who do not have evidence of immunity and are likely to be exposed to or transmit varicella, including the following: Health care workers Household contacts of immunocompromised people People who live or work in places where exposure or transmission is likely (eg, teachers, students, child care workers, residents and employes of institutional settings, inmates and employees of correctional institutions, military personnel) Women of childbearing age who are not pregnant Adolescents and adults living in households with children International travelers Postexposure vaccination with the single-antigen varicella vaccine is recommended for children with no evidence of immunity and should be offered to adults with no evidence of immunity.