Objective: To compare history of varicella with presence of varicella antibody in refugees and to determine the number of unnecessary doses of varicella vaccine administered to refugee children > or =7 years of age.
Methods: Cross-sectional study of refugees > or =7 years of age evaluated between July 2000 and October 2002 by the Refugee Health Assessment Program at Boston Medical Center. We recorded age, sex, region of origin, varicella history, and results of serologic testing for presence of varicella antibodies.
Results: Eighty-eight percent of individuals with a positive history of clinical varicella had varicella antibody; 65% of those with negative history had varicella antibody. The positive predictive value of a history of clinical varicella was 88%. The negative predictive value of a negative history was 39%.
Conclusion: History of varicella was not a reliable predictor of presence or absence of varicella antibody in refugees. Strategies to protect individuals with negative histories of clinical varicella include immediate immunization or serotesting followed by immunization of susceptible individuals. Relying on positive histories of clinical varicella may leave some individuals susceptible to varicella and impede efforts to eliminate varicella in the US.